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					                   Instrumentation Report




                            Karen Ignacio
                            Dawn Lacuesta
                            Ingrid Pascual


This exemplar prepared by the above students and used with permission.




                     Ryerson University
           Graphic Communications Management
  GRA024 Printing Processes and Quality Control (Section 003)



                Submitted to: Professor Ian Baitz
                   Friday, October 24 2003
GRA024 sec. 003 Instrumentation Report                                                               Ignacio. Lacuesta. Pascual.



TABLE OF CONTENTS:



   Dimensional Stability of Paper ................................................................................. 3
           Appendix A ................................................................................................ 9

   Curling Tendency of Paper .....................................................................................11
             Appendix B ..............................................................................................16

   Opacity of Paper (Contrast Ratio) .........................................................................22
              Appendix C .............................................................................................27

   Colour of Paper.........................................................................................................29
             Appendix D ..............................................................................................35

   Bibliography...............................................................................................................41




                                                                                                                                   2
  GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


                                    1. Dimensional Stability of Paper

  Purpose:

          The purpose of this instrumentation is to assess the physical property of paper concerning its dimensional
          stability. The test measures and compares the differences in the dimensional stability of paper of varying
          grades (uncoated, coated and newsprint) in their grain and cross grain direction when wetted. The results of
          the test are analyzed according to the average percentage size change of each paper being examined. In
          turn, this type of testing will be useful in the industry for preventing printability issues caused by
          misregistration and fan out, avoiding runability problems due to web breakage and paper jams, and
          predicting which type of paper would be most suitable for such products as business forms, close register
          print outs, maps, stamps and wallpapers.

  Definitions:

          Fanning-out of web – “An increase in web width [cause by the expansion of paper] after printing a colour,
          which causes succeeding colors to print shorter than the preceding colour (Wilson, 1998, p. 286).”

  Instruments Used:

          A. GATF Register Ruler
                 Manufactured by Theo, Altender & Sons, Phila. PA.
                 Register Rule
                 PAT. No. 2554099
                 46“
          B. Pencil
          C. Pan and water
          D. Timer

  Materials Tested:

          In order to correctly complete this test, 5 different samples of paper (2 coated, 2 uncoated, 1 newsprint) are
          obtained.

          Table 1.1 Materials Tested for Dimensional Stability of Paper

                                     M size     M Weight     Basic Size
         Paper Type                                                          Basis Weight (lb.)       Grammage (g/m2)
                                    (inches)    (inches)      (inches)
1. Colonial Glowhite Bond              23x36        106M          17x22                     23.94                    90.09
2. Rolland Opaque Offset              19x25           60M          25x38                    60.00                   88.89
3. Lumiart Gloss Book                 23x29          112M          25x38                    60.00                   88.89
4. Productolith Gloss Offset          23x35          136M          25x38                    80.25                  118.89
5. Newsprint                          25x38           66M          24x36                    30.01                    48.88




                                                                                                                      3
GRA024 sec. 003 Instrumentation Report                                                 Ignacio. Lacuesta. Pascual.


Procedure:

       1.   Acquire 5 types of papers (2 coated, 2 uncoated and 1 newsprint) and determine the grain direction of
            each paper. Cut each paper into 6 strips (3 strips grain short and 3 strips grain long) of 8.1” x 2”. Label
            the strips according to their paper type and grain direction.

       2.   Along the center of each strip, draw a straight line running off the ends with a pencil. Measure the
            length of this line with the GATF Register Ruler (up to 3 decimal places). State the length of this line
            on the strip itself.

       3.   Acquire a pan and fill it with water. Immerse each strip in water for up to 10 minutes. After the
            elapsed time, remove the strips and place them on a flat surface. With the GATF Register Ruler,
            measure the length of the line running along the center of each of the strips. Record this length as the
            strip of paper’s wet length.

       4.   Calculate and record the percentage size change of the paper. Percentage size change = [(*change in
            length / original length) x 100%].
            *Note: change in length = wet length – original length.

       5. Record the results in a table.




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           GRA024 sec. 003 Instrumentation Report                                                                     Ignacio. Lacuesta. Pascual.


           Results:

           Chart 1.1 Average Percentage Size Change of Paper Regarding Its Dimensional Stability

                                                            Average Percentage Size Change of Paper Regarding Its
                                                                            Dimentional Stability

                                                    3.00
               Average Percentage Size Change (%)




                                                    2.50

                                                    2.00

                                                    1.50
                                                                                                                                  Long Grain
                                                                                                                                  Short Grain
                                                    1.00

                                                    0.50

                                                    0.00
                                                            Colonial       Rolland     Lumiart      Production     Newsprint
                                                    -0.50
                                                                                     Paper Type



           Table 1.2 Average Percentage Size Change of Paper Regarding Its Dimensional Stability.

                                                                Grain                                      Average
                                                                                              Average Wet           Average Percentage Size Change
                                                               Direction   Average Original               Change in
       Type of Paper                                                                             Length              = (Average Change in Length/
                                                                           Length (inches)                  Length
                                                              Long Short                        (inches)             Average Original Length) x 100
                                                                                                           (inches)
1. Colonial Glowhite Bond
               1                                                ü                     8.054          8.047       -0.007                             -0.09%
               2                                                       ü              8.131          8.332        0.201                              2.47%
2. Rolland Opaque Offset
               1                                                ü                     8.122          8.124       0.002                              0.02%
               2                                                       ü              8.111          8.215       0.104                              1.28%
3. Lumiart Gloss Book
               1                                                ü                     8.021          8.013       -0.008                             -0.10%
               2                                                       ü              8.084          8.265        0.181                              2.24%
4. Productolith Gloss Offset
               1                                                ü                     8.097          8.097       0.000                              0.00%
               2                                                       ü              8.068          8.240       0.172                              2.13%
5. Newsprint
               1                                                ü                     8.089          8.077       -0.012                             -0.15%
               2                                                       ü              8.094          8.206        0.112                              1.38%

           * Note: Refer to Appendix A for a more detailed description of the experiment’s results.


                                                                                                                                                5
GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


Discussion:

       Dimensional stability is one of paper’s physical properties. It is defined as a sheet or web paper’s ability to
       withstand dimensional changes in its grain and cross-grain directions when subjected to environmental
       changes and stresses applied during printing and converting (Wilson). Moreover, this property is directly
       related to the characteristics of the cellulose fibers that make up paper. Cellulose is extremely absorptive
       due to its high affinity for water. When wetted, cellulose fibers tend to expand in width rather than length.
       As such, the dimensional stability of paper is relative to its grain direction. That is, the dimension running
       along a paper’s grain direction is likely to remain constant when wetted compared to that of the cross-grain
       direction (Wilson). Certain environmental changes that influence the dimensional stability of paper include
       changes in atmospheric temperature and relative humidity. These changes either increase or decrease the
       relative moisture content of a paper’s surrounding environment. For example, when temperature decreases,
       relative humidity increases. As such, if the relative humidity of a stack of paper’s surrounding atmosphere
       increases then the paper’s dimensions will expand and cause wrinkled edges due to its absorption of
       moisture. On the other hand, an increase in temperature causes relative humidity to decrease. In turn, the
       dimensions of a stack of paper will shrink when it’s surrounding atmosphere decreases in relative humidity
       (Wilson). Examples of printing strains that may hinder a paper’s ability to maintain a constant dimension
       are the application of excessive pressure, stretching as the sheet is peeled off a blanket and the influence of
       excessive moisture from thick ink films and fountain solution on the plates that are absorbed by the paper
       when passing through the press. Another factor that influences dimensional stability is the manufacturing
       process of converting cellulose fibers, fillers and other components into paper. The type of conversion
       method used will determine the nature of a particular type of paper. For example, Offset papers with
       characteristics such as little refining, high porosity and high filler content are more dimensionally stable
       than which are refined and have tightly bound fibers and strong sheet strength (Wilson). That is, chemical
       or mechanical refining increases fibers’ ability to bind with each other. As paper becomes more tightly
       bound, less internal spacing exists between individual fibers. This in turn causes paper to become less
       porous and less absorbent. Moreover, a decrease in internal spacing causes “expansions or contractions of
       each individual fiber [to] be translated into greater dimensional changes of the paper (Bureau, 1968 ,
       p.29).” Lastly, a high filler content in paper imparts great dimensional stability because unlike cellulose,
       fillers will be “inert moisture changes (Bureau, p.32)” Therefore, certain combinations of paper properties
       will directly influence the degree in which paper is dimensionally stable.

       In relation to the dimensional stability of paper, the following instrumentation test was conducted to imitate
       a situation in which paper becomes subjected to environmental changes and/or printing stresses that cause
       it to absorb an excessive amount of moisture. As such, two variables were tested to evaluate their relative
       influence on the overall dimensional stability of paper. The first variable tested was related to the type of
       paper. The types of paper tested are as follows: two uncoated (Bond and Offset), two coated (Book and
       Offset) and newsprint. The second variable tested was related to the paper grain direction. As such, five
       different paper types that were each cut into grain long and grain short strips were submerged in a water
       bath for ten minutes each. Each sample’s wet length was then compared with its original length in order to
       obtain the average percentage size change of each paper type. However, prior to submerging the individual
       strips, it was predicted that the dimensional instability of paper would be most evident in the grain short
       strips because it would expand much more than the grain long strips. This was predicted because of the
       cellulose composition of paper that “changes in their size much more in their girth than in their length
       (Breede, 1999, p.40).” It was also predicted that the Newsprint papers would be the most dimensionally
       stable compared to Bond paper. Newsprint would be more dimensionally stable because it is composed
       primarily of groundwood pulp and is not surface sized (Wilson). As such, newsprints have a high yield of
       lignin due to the lack of refining and are highly absorptive and porous in order to allow quick ink
       saturation. However, Bond paper was predicted to have a poor dimensional stability because it is highly
       refined in order to enhance other desirable properties such as durability and permanence. Consequently, the
       results of the experiment reflected the hypothesis mentioned above. That is, little or no dimensional
       changes occurred in the long grain direction while the majority of the dimensional changes occurred in the
       short grain direction of all five samples tested. Moreover, the Colonial Glow White Bond paper had the
       greatest average size change of 2.47% while Newsprint had the second least dimensional change of 1.38%
       next to the Rolland Opaque Offset paper with 1.28%. The Rolland Opaque Offset paper had greater
       dimensional stability when compared to the Newsprint sample because of its high filler content. Fillers are


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GRA024 sec. 003 Instrumentation Report                                               Ignacio. Lacuesta. Pascual.

       primarily added to paper in order to increase its opacity. Moreover, there is a direct relationship between
       absorbency of paper and its filler content. Paper absorbency increases linearly when additional fillers are
       added to paper because the spaces between fibers and capillaries are also reduced. Also, paper with high
       filler content is less reactive to changes in relative humidity because fillers are also inert to moisture
       changes (Wilson). As such, fillers both increase paper’s capacity to absorb moisture and improve its
       dimensional stability.

       Therefore, all paper will expand or shrink in relation to the changes in its moisture content. However, the
       short grain direction of paper is more likely to experience greater dimensional changes than that of the long
       grain direction. Moreover, the overall dimensional stability of paper is dependent on the components that
       are included in a paper’s composition.

Recommendations:

       Based on the test results regarding the percentage size change of each paper type, the following is a ranking
       of the materials in order of best to worst in printing, runability and end use suitability.

                1.   Rolland Opaque Offset
                2.   Newsprint
                3.   Productolith Gloss Offset
                4.   Lumiart Gloss Book
                5.   Colonial Glow White Bond

       Rolland Opaque Offset is the most suitable because it was the most dimensionally stable in its short grain
       direction (1.28%). On the other hand, Colonial is the least suitable because it had the greatest dimensional
       change of 2.13%.


       Printability:
               A primary factor that influences good print quality output is registration. That is, proper
               registration ensures an accurate positioning of an image in relation to another image printed on a
               sheet between subsequent passes on press and between colors printed. To ensure minimum
               registration problems it is important that paper maintains its dimensional stability when passing
               through the press. The more stable the dimensions of a paper are when subjected to moisture
               changes the more suitable the material is to reproduce an image to its highest quality with a given
               printing process. As such, it is recommended that the running direction of a sheet when passing
               through a press should be in its long grain. This direction is most suitable because it is the side
               most resistant to moisture change. Moreover, cross-grain expansion of paper often leads to
               printability problems such as fan out. This is often caused after printing the first color “which [in
               turn] causes succeeding colors to print shorter than the proceeding color (Wilson, p.286).”

       Runability:

               A runability issue related to paper expansion is web breakage on press due to the applied web
               tension. Web breakage is often caused by the reduction of paper strength after its expansion due to
               excessive moisture intake (i.e. from fountain solution in an offset press) (Choi, Echt, Gast,
               Niskanen, Tattari, 2001). Moreover, poor dimensional stability may also cause stoppages on press
               due to paper jams. The jamming of paper between press units can be caused by the rapid
               expansion of paper due to its absorption of ink and fountain solution from the image and non-
               image areas on the plate. As such, moisture changes that cause expansion and wrinkled edges may
               in turn inhibit the paper from running smoothly through the nips between the blanket and
               impression cylinders. Therefore, in order to minimize the occurrence of web breakage or jamming
               on press it is important to use web paper that is very dimensionally stable.




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GRA024 sec. 003 Instrumentation Report                                          Ignacio. Lacuesta. Pascual.



End use:

             Dimensional stability is an important requirement for business forms and other papers used for
             personal use and computer printouts. These types of paper must be dimensionally stable because
             they must be able to withstand continuous printing, assembling and collating into numerous sets.
             Moreover, dimensional changes must be kept at a minimum when dealing with continuous
             business forms because “close registration [is] required between binding, folding and die cutting
             (Wilson, p.202).” Other end uses for dimensionally stable papers are for products that require an
             application of adhesives. These products include such things as stamps and wallpaper. Moreover,
             maps also require dimensionally stable papers because they are often used outdoors and are subject
             to the varying changes in atmospheric conditions. Lastly, any product that calls for close
             registration printing requires paper with high dimensional stability. Such products include machine
             read scanner sheets and cheques.




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GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


                                    2. Curling Tendency of Paper

Purpose:

       The purpose of this test is to observe the curl tendency of each sample of paper. The results of this test will
       be important in evaluating whether the curl is on the felt or wire side, whether the paper curls towards or
       away from the wetted side and if the curl is parallel to the grain, or perpendicular to the grain. As such,
       applying the specific information gained about the curl characteristics of a particular type of paper will be
       useful in avoiding curling problems relating to printability, runability and enduse. Also, the information
       gained from the results will aid in the increase of print productivity by helping operators recognize the
       most suitable papers to use for a particular printing process and the necessary steps to take in order to
       prevent paper curl from occurring.



Definitions:

       Inherent Curl – (one of the two main categories of paper curl) curling that occurs immediately after the
       paper is first sheeted (Bureau, 1968).

       Moisture Curl – (one of the two main categories of paper curl) curling that occurs when the moisture
       content of paper becomes equilibrium with the relative humidity of its surrounding atmosphere (Bureau).

       Reverse Curl – Occurs when paper curls towards the wetted side (Wilson).

       Permanent Curl – Caused by applied moisture in the press and is mostly noticeable in thinner types of
       papers. As paper reacts to m  oisture it curls away from wetted side, but as its dries it curls towards the
       wetted side and takes on a permanent curled form (Wilson).

Instruments Used:

       A.   A wrung-out sponge
       B.   Litho Stone (Plate)
       C.   2 rollers
       D.   Hold down tool (necessary for measuring curl)
       E.   Ruler with centimeters and millimeters



Materials Tested:

       In order to correctly complete this test, 5 different samples of paper (2 coated, 2 uncoated, 1 newsprint) are
       obtained.

       Table 2.1 Materials Tested for Curling Tendency of Paper

                                    M size                    Basic Size                                                 2
         Paper Type                             M weight                      Basis Weight (lb.)     Grammage (g/m )
                                   (inches)                    (inches)
1. Colonial Glowhite Bond             23x36          106M          17x22                    23.94                   90.09
2. Luna Matte                          26x40         132M          25x38                    60.29                   89.32
3. Earnscliffe                         19x24          58.5        17 x 22                   23.99                   90.28
4. Productolith Gloss Offset           23x35         136M           25x38                   80.25                 118.89
5. Newsprint                           25x38          66M           24x36                   30.01                  48.88



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GRA024 sec. 003 Instrumentation Report                                               Ignacio. Lacuesta. Pascual.




Procedure:

       1.   Select 5 different samples of paper (2 coated, 2 uncoated, 1 newsprint). Note each sample type.

       2.   For each paper sample, determine and indicate the felt and wire side, and the grain direction of the
            paper (grain long, grain short).

       3.   For each sample, cut 6 squares of exactly 5 5/8”, with the grain direction along the diagonal of the
            square (corner to corner).

       4.   Using a wrung-out sponge, dampen a plate with water, and then use a roller to roll off the excess water.
            Firm pressure must be applied in order to remove excess water.

       5.   Quickly put the sample on the damp plate, and using a dry roller, roll it once over and back with
            medium pressure.

       6.   Carefully lift the wetted sample, and wait for any initial curl to reverse. Hang the sample to dry by the
            least curled corner for 15 minutes.




                                                                                                                   10
       GRA024 sec. 003 Instrumentation Report                                                                                        Ignacio. Lacuesta. Pascual.


       Results:

                                  Table 2.2 Total Average Curl Across or With Grain Direction on Side Wetted

                                                                   Felt Side Wetted                                                Wire Side Wetted
                                                           Average Curl       Average Curl                                 Average Curl       Average Curl
              Paper Type
                                                           Across Grain        Along Grain                                 Across Grain        Along Grain
                                                           Direction (cm)     Direction (cm)                               Direction (cm)     Direction (cm)
1)   Luna Matte (Short Grain)                                                  -0.47                           -0.89                            -0.90                         -0.20
2)   Productolith (Grain Long)                                                 -1.62                           -1.80                            -1.19                         -2.05
3)   Colonial (Grain Long)                                                     -1.60                           -1.35                            -0.82                         -2.50
4)   Earnscliffe (Grain Long)                                                  -0.79                           -0.85                            -0.98                         -1.32
5)   Newsprint (Grain Long)                                                    -0.42                           -1.60                            -0.54                         -1.55



                                  Chart 2.1 Total Average Curl Across or With Grain Direction on Side Wetted


                                           Total Average Curl (cm) Across or Along Grain Direction on Wetted Side

                                                            Felt Side Wetted                                                    Wire Side Wetted
                                        Average Curl Across Grain        Average Curl Along Grain         Average Curl Across Grain            Average Curl Along Grain
                                             Direction (cm)                   Direction (cm)                   Direction (cm)                       Direction (cm)
                                0.00


                                -0.50
          Degree of Curl (cm)




                                -1.00


                                -1.50


                                -2.00


                                -2.50


                                -3.00
                                                                                             Side Wetted

                  1) Luna Matte (Short Grain)        2) Productolith (Grain Long)   3) Colonial (Grain Long)     4) Earnscliffe (Grain Long)     5) Newsprint (Grain Long)




                                  * Note: Refer to Appendix B for a more detailed description of the experiment’s results.




                                                                                                                                                                             11
GRA024 sec. 003 Instrumentation Report                                               Ignacio. Lacuesta. Pascual.


Discussion:

       Each sample of paper was tested in order to determine its curling tendency. From the results obtained from
       each sample, it was observed that the majority of the curls were away from the wetted side for both the
       wire and felt side, and that most of the observed curls were with the grain direction of the paper. There are
       various factors that may have influenced the results, and in order to gain a broad explanation of the curling
       tendency of paper, it is essential that each of these factors are discussed and analyzed.

       Paper curl is a problem that is associated with the dimensional stability of paper. It occurs when there is in
       an unequal amount of moisture on both the felt and wire side of the paper. As such the paper will enlarge
       structural changes. This means that paper will curl if one side gains or looses more moisture than the other
       side (Wilson). For the purpose of the test, each paper sample was dampened then dried, causing it to absorb
       water and contract. The results of the test can be explained by examining the various types of paper curl
       and the two main categories in which they fall in; an inherent curl and a moisture curl. An inherent curl
       becomes apparent when paper is first sheeted and a moisture curl occurs when the moisture of the paper
       becomes equal to that of its surrounding atmosphere (for example, the relative humidity of the press room
       where the paper is stored) (Bureau). The results of the test can also be explained by considering the
       influence of properties, such as paper grain and fiber orientations, on the curling tendencies of paper.

       The variations with the fiber orientation of paper and the differences between the felt side and the wire side
       are the basic causes of paper curl. For example, the samples utilized in our test were placed on the
       dampened plate either felt or wire side (because the moisture that was influenced by the damp plate caused
       the sample to expand). The sheet curled away from the side that it was wetted because its fibers expanded
       when they came in contact with the moisture that was influenced by the dampened litho stone. Moreover,
       when paper that has been moistened begins to dry, the curls tend to go towards the direction of the wetted
       side. This type of curl is referred to as reverse curl (Wilson). As mentioned, the variance in the fiber
       orientation of paper can influence its curling tendency. Due to this fact, when paper is wetted on both sides
       and looses moisture, it will likely curl towards its wire side, parallel to its grain. When paper gains
       moisture, it will likely curl towards the felt side (Wilson). Another type of curl that may cause problems
       during printing is known as permanent curl. This type of curl is caused by moisture in the press and is one
       of the most commonly occurred inherent curl (Abbott, Scott, Trosset).

       It is also important to consider that treatments that are performed prior to papermaking process, such as
       beating and refining can also influence the curling tendency of paper (Bureau). For instance, paper that has
       been highly refined, are more likely to curl due to the effects of the changes in relative humidity (Wilson).
       Yet, the more obvious factors that would cause curling, is the weight of the paper. Much like the newsprint
       sample used in the test, light weight papers have a greater tendency of curling, since they are less stiff
       which offers minimal resistance to factors that may influence curling. Another important factor to consider
       that may have influenced the curling tendency of each sample paper is its grain direction. When the
       moisture content of paper changes, it will expand or contract more across its grain direction due to the
       physical characteristics of its fibers (Bureau).

       In observing each result, the importance of further understanding the properties and characteristics of paper
       is emphasized. In considering factors such as the dimensional stability, it will assist in how paper should be
       handled in the press room, in order to avoid problems such as curling. Proper consideration and knowledge
       will provide better end use results and runability in the press.




                                                                                                                  12
GRA024 sec. 003 Instrumentation Report                                                  Ignacio. Lacuesta. Pascual.


Recommendations:

       Based on the test results regarding the curling tendencies of each paper type, the following is a ranking of
       the materials in order of best to worst in printing, runability and end use suitability according to its average
       curl. It is important to note that the average curls varies in results depending on the side which was wetted
       (felt or wire side). Refer to results.

       1.   Earnscliffe
       2.   Newsprint
       3.   Luna Matte
       4.   Productolith Gloss Offset
       5.   Colonial Glowhite Bond

       However, it is highly recommended that all these types of paper should not be utilized for certain jobs that
       will require excessive exposure to changes in mois ture conditions.

       Printability:

                When printing a job, it is important to consider the most suitable type of paper that will reproduce
                an acceptable image. Paper that has a high tendency of curling will cause problems with
                registration, which will significantly affect the final result of the print job. The paper samples
                which we utilized for out test have a high curling tendency when they are placed in poor
                atmospheric conditions. So therefore, if paper is to be used successful in a print job, it must be
                handled properly to avoid problems such as misregistration. As such, papers with high curling
                tendencies should be temperature conditioned prior to placing them on the press. This procedure
                will minimize registration problems by reducing the possibility of dimensional changes in the
                paper.



       Runability:

                It is important that paper that is used in certain presses, such as an offset press, is able to withstand
                considerable stress without curling. In the case of the offset press, the separation of paper from the
                offset blanket can cause mechanical stress, so paper that is unable to endure exceeding amounts of
                pressure, such as the samples we have used in our test would most likely curl, causing printing
                jams or possible tearing. Paper that is also more reactant to moisture and result in developing
                types of curl such as a permanent curl should also not be used in order to prevent improper
                delivery and jogging of the printed sheets.



       End-use:

                Curling of paper can significantly affect the intended end use of a printing job. For instance, a
                printer should not consider using the samples used in the test to print wallpaper, since all samples
                exhibited high curling tendencies when moistened. It will also not be suitable use for printing
                posters/billboards that are intended to be used for outdoors and other such end uses that require
                high tolerance to moisture and atmospheric effects. Lastly, papers with curling resistance should
                not be utilized for jobs that require accurate registration such as business forms, and security
                cheques.




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GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


                                            3. Opacity of Paper


Purpose:

        The purpose of this instrumentation is to assess the optical property of paper regarding its opacity. In this
        test the opacity readings obtained will be dependent on 5 varying paper samples (2 uncoated, 2 coated and
        1 newsprint). As such, a comparative analysis will be conducted between the samples according to both
        their average opacity reading and the varying range differences amongst the readings. In turn, conclusions
        made based on the findings will be useful in the industry for preventing printability issues related to show
        through and color contrast, avoiding runability problems due to and predicting which type of paper would
        be most suitable for such products as envelops,

Definitions: No definitions necessary.

Instruments Used:

        A. CRI Criterion
                Reflection Meter
                Model CG-6 Ser. 1959
                Made by Canadian Research Institute Division of Criterion Instrument Ltd.
                Don Mills, Ontario, Canada

Materials Tested:

        In order to correctly complete this test, 5 different samples of paper (2 coated, 2 uncoated, 1 newsprint) are
        obtained.

        Table 3.1 Materials Tested for Opacity of Paper

                                    M size      M weight       Basic
         Paper Type                                                        Basis Weight (lb.)      Grammage (g/m2)
                                   (inches)     (inches)       Size
1. Colonial Glowhite Bond             23x36         106M        17x22                     23.94                   90.09
2. Rolland Opaque Offset              19x25          60M        25x38                     60.00                   88.89
3. Lumiart Gloss Book                 23x29         112M        25x38                     60.00                   88.89
4. Productolith Gloss Offset          23x35         136M        25x38                     80.25                 118.89
5. Newsprint                          25x38          66M        24x36                     30.01                  48.88




                                                                                                                   14
GRA024 sec. 003 Instrumentation Report                                               Ignacio. Lacuesta. Pascual.


Procedure:

       1.   Acquire 5 types of papers (2 coated, 2 uncoated and 1 newsprint) and label accordingly.

       2.   Ensure that the test is performed on the same side (felt or wire) of each sample. Mark the side to be
            tested. Also, make sure that the area in which the paper is managed is not the same area in which the
            test will be conducted.

       3.   Obtain opacity readings from the CRI Criterion with the 45° (round) head. Prior to obtaining the
            necessary readings, ensure that the machine has warmed up for one hour or more. It is also important
            the Zero Suppression toggle is OFF.

       4.   With the chosen side to be tested (felt or wire), place the sample over the reading head opening with
            the white standard as its backing. Use the sensitivity control knobs to calibrate the meter reading to
            100.

       5.   After calibration, obtain opacity value readings directly from the meter face with the black standard
            backing the sample. Repeat the following step 20 times for each paper type. Make sure to recalibrate
            for each paper sample tested.

       6.   Record results in a table.




                                                                                                                     15
      GRA024 sec. 003 Instrumentation Report                                                                        Ignacio. Lacuesta. Pascual.


      Results:

                                           Table 3.2 Average Percentage Opacity Readings

                                                                                             Type of Paper
                                                                  Colonial Glowhite           Rolland         Lumiart Gloss
                                              Newsprint             Bond (23x36 -          Opaque Offset          Book           Productolith Gloss
                                            (25x38 - 66M)              106M)               (19x25 - 60M)      (23x29 - 112M)    Offset (23 x 35 -136M)
Average
Percentage
Opacity
Reading (%)                                           92.83                     95.30                 97.25             96.23                        97.78
Range of
Readings                                     92.50 - 93.00               95.00 - 96.00       97.00 - 97.50      96.00 - 96.50             97.50 - 98.00

                                           Chart 3.1 Degree of Paper Opacity in Relation to Its Felt Side



                                                        Degree of Paper Opacity in Relation to Its Felt Side

                                          99.00

                                          98.00
         Percentage Opacity Reading (%)




                                          97.00                                                                     Newsprint
                                                                                                                    (25x38 - 66M)
                                          96.00
                                                                                                                    Colonial Glow White Bond
                                          95.00                                                                     (23x36 - 106M)
                                                                                                                    Rolland Opaque Offset
                                          94.00
                                                                                                                    (19x25 - 60M)
                                          93.00                                                                     Lumiart Gloss Book
                                                                                                                    (23x29 - 112M)
                                          92.00
                                                                                                                    Productolith Gloss Offset
                                          91.00                                                                     (23 x 35 -136M)

                                          90.00

                                          89.00
                                                  1    3      5      7     9   11     13    15   17    19
                                                                      Reading Number



                                           * Note: Refer to Appendix C for a more detailed description of the experiment’s results.




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GRA024 sec. 003 Instrumentation Report                                                  Ignacio. Lacuesta. Pascual.


Discussion:

      When light strikes an object, the light is reflected, transmitted or absorbed. However, paper transmits light
      in the following manner: it can either scatter the light rays or it can transmit parallel rays that do not possess
      the ability to scatter (Wilson). The amount of light that is scattered plus the parallel rays, will determine the
      opacity level of the paper. Opacity is one of the optical properties of paper. It can be defined as the ability
      of paper to prevent light from showing through by means of absorbing and scattering the light as it passes
      from the air to the fiber and back to the air (Abbott, Scott, Trosset). Moreover, the opacity level of paper is
      measured on a 0 – 100 percentage scale in which a reading of 100% represents paper that blocks off all
      light. On the other hand, a reading of 0% means that the paper transmitted all of the light. In order to gain a
      better comprehension of the factors that may have affected the results of the test, it is important to examine
      the various influences that may affect the opacity of paper. There are several important factors that
      influence the opacity of paper. These factors include the dyes and fillers contained in the content of the
      paper, the pulp fibers of the paper and the overall weight of the paper.

      Dyes affect the opacity of paper by increasing it. This is due to the fact that dyes are able to independently
      absorb and scatter light, making them an additive to the paper’s opacity (Abbott, Scott, Trosset). Fillers
      affect the opacity of paper in a similar way. That is, fillers are additives that increase the scattering of light,
      depending on the level of the filler’s refractive index. The higher the refractive index of the filler, the more
      opaque the paper becomes (Abbott, Scott, Trosset). The filler’s size and how it scatters throughout the
      paper also affect the opacity of paper. For instance, fillers that has a diameter that is less than one half the
      wavelength of the light passing through the paper will not scatter light. Similarly, fillers that are not
      properly dispersed, allow for more optical contact. Optical contact occurs when light is able to pass to one
      fiber to another without passing through air (Abbott, Scott, Trosset). In turn, this affect will decrease the
      opacity of paper, since the scattering of light is reduced to a minimum.

      As mentioned, the pulp fibers of the paper can also affect the paper’s level of opacity. This result is
      affected by the fineness of the fibers, or in other words, the total diameter of the fiber. For example, the
      opacity of groundwood pulp used to make newspapers will increase when its diameter fiber increases.
      However, as with any pulp, the amount of opacity level desired can only be obtained through paper making
      process factors such as beating and calendaring which affect the degree of bonding between the fibers
      (Abbott, Scott, Trosset). The length of fiber would not have as much of a significant affect on the opacity
      of paper as its diameter. This is due to the fact that fibers lie in the plane of the paper and light would only
      pass through when they cross (Abbott, Scott, Trosset). Similar to the effects of the paper’s fiber diameter to
      its opacity, the weight of the paper can also impact its opacity level by increasing it, depending on the
      increased weight of the paper. This occurs mostly because as the weight of the paper increases then so do
      its thickness. As such, there is an increase in light scatter by the sheet (Abbott, Scott, Trosset).

      As the results of the test have shown, each of the paper samples that were tested all posses’ high levels of
      opacity because the overall readings were found in the 90th percentile. Newsprint, being that it possess the
      lowest level of opacity result in the test, would usually posses an exceptionally high level of opacity.
      However, reductions in the basis weight of newsprint tends to decrease its opacity level, allowing for more
      show through as mentioned about the affects of the w         eight of the paper on its opacity level (Wilson).
      Similarly, Productolith displayed the highest level of opacity in comparison to the other samples tested.
      This result may have been greatly influenced by its overall basis weight. As discussed, greater thickness of
      the paper allows for an increase in the ability to scatter and absorb light, therefore increasing opacity. The
      information reviewed in order to gain a broader understanding of the results of the test, is critical in order to
      make the right decisions as to what paper is most suitable for certain types of print jobs that require high
      opacity in paper. It is essential in order to avoid problems such as show-through which will affect the
      overall presentation of the printed job.




                                                                                                                      17
GRA024 sec. 003 Instrumentation Report                                                 Ignacio. Lacuesta. Pascual.


Recommendations:

       Based on the test results regarding the ranges and average opacity readings per paper type, the following of
       is a ranking of the materials in order of best to worst in printing, runability and end use suitability.

                1.   Productolith Gloss Offset
                2.   Rolland Opaque Offset
                3.   Lumiart Gloss Offset
                4.   Colonial Glowhite Bond
                5.   Newsprint

      Since it is desirable to have opaque papers for 99% of printing jobs, Productolith Gloss Offset would be the
      most suitable because it has the highest average of 97.78% on the opacity scale. On the other hand,
      Newsprint would be the least suitable because its average opacity reading of 92.83% is the lowest out of the
      materials tested.

       Printability:

               For most print jobs, maximum print contrast is required. This is best achieved when you use a
               bright blue-white paper that has adequate opacity and is printed with the highest possible ink film
               density. A lack of sufficient paper opacity will result in an excessive show-through and will in turn
               reduce print contrast. Print contrast is significantly important in a print job, because it is the
               varying densities in the highlight tones, midtones and shadow tones that create noticeable detail
               within an image (Wilson). Paper that is low in opacity, will allow show-through, which will affect
               the print contrast of a printed job. Hence, the job will produce a bad print quality. In order to avoid
               this incidence, ensure that there is no reduction in basis weight or grammage because this has the
               tendency to reduce opacity and increase show-through.


       Runability:

               The opacity of paper must be sufficient to hold adequate number and sizes of pores to control ink
               absorption. Failure to evaluate this characteristic of paper will result in excessive ink penetration
               on the substrate and will cause runability problems such as unevenness paper surface that may
               cause tearing of paper. Therefore, if a high print contrast job is required, it is better to have a great
               value of opacity to reduce the likeness of show-through and in turn prevent excessive ink
               absorption.

       End-use:

               Although jobs may differ from each other, most of them demand for opaque papers or substrates.
               Thus, in a job where brightness is not necessary, papers or substrates that will provide high opacity
               and less show through are with colors like blue, green, and grey because they have higher light
               absorption. It is also suggested to evaluate the paper’s finish, bulk level, degree of refining and
               calendaring to determine the degree of a substrate’s opacity. For instance, if you want to attain a
               readable textbook, the paper must be 100% opaque in order to absorb the sunlight or any light,
               rather than reflecting it where it is harder for the eyes to read and focus on. Also, paper used in
               perfecting books, where as both sides of the sheets are printed require high opacity in order for the
               text to be legible to the reader. Other examples of jobs that require paper of high opacity are jobs
               intended for security purposes such as security envelopes. The paper used must contain a high
               opacity level in order to meet the requirements of its intended endues.




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GRA024 sec. 003 Instrumentation Report                                                 Ignacio. Lacuesta. Pascual.


                                                        4. Color of Paper


Purpose:

         The purpose of this instrumentation is to evaluate the optical property of paper regarding color variations of
different types of paper, in terms of its lightness from blackness to perfect white, redness, greenness, blueness and
yellowness. This implies similar ways that the human eye discerns from the spectral distribution of light for the
color spectrum. This test is also useful when color formulation and ink-color quality control are needed, in order to
produce good print quality of the job. Evaluating the color of paper will help avoid runability problems due to web
breakage and paper jams caused by the unevenness of the paper surface. In turn, this will predict which color of
paper would be most suitable for such products as commercial advertising billboards, short and long documents.



Definitions:

         CIE – “stands for Commission Internationale de l’Eclairage (the International Commission on
         Illumination) and an international standards-setting organization for colorimetry and related measurements
         (Field, 1999, p.425).”

         Colorimetry – “a branch of color science concerned with measuring and evaluating the colors of objects
         and images (Field, p.427).”



Instruments Used:

         A. Spectrophotometer – Hunter Lab: Color Quest: Hunter Associates Laboratory, Inc: Reston, Virginia,
            22090
                • Standards: Hunter Laboratory, Inc.: Reston, Virginia, 22090
                      i. White Tile: CT – 1100 Color Quest; Standard No. – C5055; Geometry Illuminate: D65 -
                         2°, View - 8°; Assigned Values: X = 81.71, Y = 86.51, Z = 94.35
                     ii. Grey Tile: CT – 1100 Color Quest; Standard No. – C5055; Geometry Illuminate: D65 -
                         2°, View - 8°; Assigned Values: X = 49.26, Y = 52.45, Z = 57.28
                    iii. Black Standard (hollow tube) - CT – 1100 Color Quest

Materials Tested:

         In order to correctly complete this test, 5 different samples of paper (2 coated, 2 uncoated, 1 newsprint) are
         obtained.

         Table 4.1 Materials Tested for Color of Paper

                                      M size                    Basic Size                                                2
           Paper Type                             M weight                     Basis Weight (lb.)     Grammage (g/m )
                                     (inches)                    (inches)
 1. Colonial Glowhite Bond              23x36         106M           17x22                   23.94                   90.09
 2. Luna Matte                           26x40        132M           25x38                   60.29                   89.32
 3. Earnscliffe                          19x24         58.5         17 x 22                  23.99                   90.28
 4. Productolith Gloss Offset            23x35        136M            25x38                  80.25                 118.89
 5. Newsprint                            25x38         66M            24x36                  30.01                  48.88



                                                                                                                    19
GRA024 sec. 003 Instrumentation Report                                                 Ignacio. Lacuesta. Pascual.


Procedure:

       1.   Acquire 5 types of papers (2 coated, 2 uncoated and 1 newsprint).

       2.   The test will be conducted with the spectrophotometer, therefore turn it on.

       3.   You will be required to type the following in order: This will allow an individual to activate the
            system.

                - C:\ <enter>
                - cd ucs <enter>
                - color <enter>
            Press any key to continue, and then follow the order of functions to press:
                F 10 – Cancel
                F3 – Change Operating Modes
                F1 – Reflectance/Transmittance Modes
                F2 – Reflectance Specular Excluded (“Mode” field will only change, not the screen)
                F10 – Finished
                F4 – Change Color Scales
                F2 – Hunter L a b (“Scale” field will only change, not the screen)
                F10 – Finished
                F10 – Finished
                F2 – Instrumentations Standardization (Follow the red on screen instructions) – this is done in
                order to calibrate the instrument. First, an initial reading is taken without anything placed in the
                spectrophotometer. Then the red on-screen instructions will list the standards to place on the
                instrument, such as the white, black and grey standards.

            When finished calibrating the instrument, the following should be executed: (These following steps
            will be repeated until all required substrates are read.)

                F3 – Change Operating Modes
                F8 – Data Logging Parameters
                F1 – Select Log File
                F2 – Create Log File: Type the file name (max of 8 characters – letters and numbers only and it is
                suggested that it is relevant to the group initials or type of paper being tested: i.e. LIPNEWS)

                F10 – Finished
                F10 – Finished
                F3 – Auto Sample Numbering Currently Enabled
                F10 – Finished
                F10 – Finished
                F10 – Finished
                F5 – Color Differences

                Place the sample paper into the device

                F1 – Read Sample (this will read the paper place in the view of the spectrophotometer)
                F3 – Update Standard (to erase any old, extraneous readings)
                F1 – Read Sample (this will be reading the same sample placed earlier on)
                F5 – Store (this will save the reading taken in that portion of sample viewed, repeat this and the
                previous step as many times required – 10 readings on the same side but different sections of
                paper)

                F10 – Finished (when the current substrate is read as many times required)




                                                                                                                       20
GRA024 sec. 003 Instrumentation Report                                             Ignacio. Lacuesta. Pascual.

                Then you must repeat all these steps from the beginning (F3) to continue reading the other
                required substrates (4 other paper type).

            The following steps will only be executed if all the required substrates are read (5 types of paper):
                F10 – Finished
                Exit – (Y)es
                C:\UCS > statpak <enter>
                F3 – Specify Reference Standard
                F3 – Retrieve Standard from Standards File: Move the cursor to “Pure White” by using arrow keys
                F2 – Retrieve Standard (Red status line at the bottom will only change, not the entire screen)
                F10 – Finished
                F10 – Finished
                F1 – Specify Processing Parameters
                F3 – Change Color Scales
                F2 – Hunter L a b (“Scale” field will only change, not the screen)
                F10 – Finished
                F10 – Finished

            The steps to follow are to be repeated until all required files are printed:
                F2 – Access Data Log Files: Move cursor to previously saved file (i.e. LIPNEWS) by using arrow
                keys
                F1 0 Retrieve Log File (Red status line at the bottom will only change, not the entire screen)
                F10 – Finished
                F4 – Specify and Produce Report: Press any key to print
                F10 – Finished
            Repeat all the steps from the beginning (F2) until all the required files are printed (4 more other
            substrate file)

            When the individual has finally printed all 5 files: press F10
            Exit – (Y) es
            Then turn off the device, on the power bar.

       4.   Analyze the printed results




                                                                                                              21
GRA024 sec. 003 Instrumentation Report                                         Ignacio. Lacuesta. Pascual.


Result:

        Table 4.2 Spectrophotometer Readings for Samples Tested


                                                                    Readings
            Paper Type
                                         Average         Variance         Maximum            Minimum
Colonial Glowhite Bond
L                                               93.66             0.01              93.79            93.47
a                                               -0.43                0               -0.41            -0.45
b                                               -0.79                0               -0.73            -0.83
Earnscliffe Linen Bond
L                                               92.67             0.01              92.82            92.49
a                                                -0.6                0              -0.58            -0.63
b                                                1.33                0               1.36              1.31
Productolith Gloss Offset
L                                               91.06             0.37              91.39            89.28
a                                                0.32             0.03                 0.4            -0.21
b                                               -1.65             0.07               -1.48            -2.46
Luna Matte Gloss Book
L                                               92.36                0              92.39            92.31
a                                               -0.03                0               0.03             -0.04
b                                               -0.48                0               -0.39            -0.53
Newsprint
L                                               81.51             0.05              81.78            81.07
a                                                2.21                0               2.34               2.1
b                                                4.52                0               4.63              4.42

        * Note: Refer to Appendix D for a more detailed description of the experiment’s results.




                                                                                                       22
GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


Discussion:

       This instrumentation test is implemented to ensure the consistency of the paper colour, in case of specific
       job requirements. This experimentation was developed to examine paper’s optical properties regarding its
       colour by determining specific ways in which human observers respond to the spectral distribution of light
       for the colour spectrum. As such, to the human eye there are 3 different primary colors: red, green, and
       blue. Since these primary colors can’t be measured at the same time to uncover variations, a color scale
       was developed. “The values X, Y, and Z were used to classify a colour in terms of its primaries: red, green
       and blue. All the colour scales are based on the CIE Standard Observer data, referred to as the CIE
       Standard Observer, or the normal eye (Wilson, 1998, pg. 182).”

       When measuring white or colored papers, such as this instrumentation test have done, the CIE X, Y, Z and
       the Hunter L, a, b values were used. The Hunter L, a, b values were developed by Dr. Richard Hunter and
       this colour scale is widely used in the printing industry. The values L, a, b signify certain optical properties
       of paper, such as L for the degree of lightness (0 – 100), a measures redness and greenness (+100 >0> -
       100), and b measures yellowness and blueness (+100 >0> -100). The degree of lightness has a range of 0 to
       100, 0 indicates blackness and 100 indicates perfect whiteness. Perfect whiteness of paper is presently
       unattainable, because that would give a measure of L=100, a=0, and b=0, which no papermaking company
       has yet been able to produce. Today’s papers only come close with measures ranging in the 90’s. Since it is
       evident that a and b values of paper will always be present, the range of measure for a and b is somewhat
       similar, the +100 suggests the redness and yellowness, -100 denotes greenness and blueness and 0 indicates
       grayness. Notice that the positive measure implies warmer colors as oppose to the negative measure that
       implies cooler colors and the 0 measure indicates neither warm nor cool colors hence it is grey (Wilson).

       “As the Hunter L, a, b scale was established, an instrument called a spectrophotometer was integrated with
       the use of scales and was utilized to measure the colour of paper as a wavelength analysis of its reflected
       light against a substrate (Wilson).” “Spectrophotometers are also used as a method of characterizing the
       absorption properties of any given colour (Field, pg. 85).” This precision instrument requires a
       knowledgeable operator in order to analyze the collected quantitative information in forms of readings,
       provided. For example, in this instrumentation, the spectrophotometer takes a reading from that section of
       the paper exposed to the device, every time the substrate is clamped to the instrument. As part of the
       experiment’s requirements, a total of 10 readings were taken for each of the 5 different types of paper, and
       an average reading was provided.

       In terms of the results of the readings taken from each type of paper, it revealed that there is an average
       reading of 91.71 lightness, 0.145 redness and -1.065 blueness between the coated papers, Luna Matte Gloss
       Book and Productolith Gloss Offset. The average readings of both uncoated papers were: 93.165 lightness,
       -0.515 greenness and 0.27 yellowness, for Earnscliffe Linen Bond and Colonial Glow White Bond. Lastly
       the average results of the readings on the newsprint type of paper were: 81.51 lightness, 2.21 redness and
       4.52 yellowness. According to these average outcomes, it is reasonable to assume that the uncoated papers,
       Colonial Glow White Bond and Earnscliffe Linen Bond, have attained the closest pure white colour
       compared to the others. This is due to the fact that there is minimal or no coating applied, whereas the
       coated papers do and the newsprint’s makeup components resulted in its brownish colour due to its high
       lignin content. The results also revealed that the uncoated paper, Colonial Glow White Bond possessed the
       most consistent colour compared to others because it achieved the least variance of 0.08 between the
       maximum and minimum reading. The newsprint attained the poorest colour consistency due to a difference
       of 2.11 between the maximum and minimum reading obtained.




                                                                                                                   23
GRA024 sec. 003 Instrumentation Report                                              Ignacio. Lacuesta. Pascual.


Recommendations:

       Printability:

              In order to attain a good print quality in terms of the colors of paper used, the closest the colour of
              paper is to “pure white” the better. Because studies showed that most readable media is that which
              contain the greatest colour contrast. In turn, the best colour contrast would be black text on a white
              substrate. However, the selection of paper colors varies depending on the requirements of a job.
              Needless to say, printing papers aren’t always “white”; they may come in forms of other colors to
              suit the needs of clients. Another factor that affects the print quality of a job is the use of the 4
              process colors. The process colors: Cyan, Magenta, Yellow, and Black, are made transparent in
              order to show through each other, to create the desired image’s colour, and on the colour of the
              paper. If the paper is unable to achieve colour closest to “pure white” and in turn has other visible
                                                                                            ill.
              colors, this will lessen the overall print and colour quality of the job w For that reason, the
              appropriate colour of paper must be selected and matched for that particular job on hand.

       Runability:
              Having selected a colored paper, for instance a pastel blue bond paper, it is very important to know
              if the colour of the sheet is constant. This means that if a spectrophotometer is used to evaluate this
              pastel blue paper, the readings taken in different sections of the sheet should be consistent. If the
              readings cover a large range of measure, this means that the paper may be “blotchy” in terms of its
              coloring (Baitz). This in turn will present a rrunability problem, since the blotchiness creates an
              unevenness on the surface of the paper. This might produce unavoidable, excessive ink holdouts
              that may also produce setoff proble ms in the delivery. Therefore, the quality of colored paper
              should be analyzed in order to prevent any mishaps during the press run.

       End-use:

              To satisfy the end users of a printed material, in terms of colour of paper, it is important to
              recognize the ability of a published material to serve its purpose. For example, if the job was to
              print commercial advertising billboards, the colour of paper or the substrate plays a significant role
              in fulfilling its design. Therefore, colour matching has to be implemented prior to printing the job;
              the colour of the substrate must be carefully selected to meet the client’s and job’s needs. For
              instance, if the billboards need solid colors, then the substrate must be examined to ensure that it
              possesses exceptional fade resistance to compensate for any possible fading as it ages, such a
              newsprint would turn yellowish in this case. It is also suggested in this case that the substrate
              resistance must be investigated in order to ensure the ability of the billboards to withstand
              environmental conditions, such as rain, sunlight and cold temperatures. In terms of long
              documents, it is advised to use colour casted paper as a substrate for the text because it provides
              ease in reading as oppose to a bright white paper. Hence, adequate contrast is implemented on long
              documents as oppose to short documents and ads that require high contrast in both paper colour
              and ink colour.




                                                                                                                 24
GRA024 sec. 003 Instrumentation Report                Ignacio. Lacuesta. Pascual.


                                         Appendix A




                                                                              25
GRA024 sec. 003 Instrumentation Report                Ignacio. Lacuesta. Pascual.


                                         Appendix B




                                                                              26
GRA024 sec. 003 Instrumentation Report                Ignacio. Lacuesta. Pascual.


                                         Appendix C




                                                                              27
GRA024 sec. 003 Instrumentation Report                Ignacio. Lacuesta. Pascual.



                                         Appendix D




                                                                              28
GRA024 sec. 003 Instrumentation Report                                                Ignacio. Lacuesta. Pascual.


                                                 Bibliography


Abbott, J. C., Scott, W. E., & Trosset, S. (1995). Properties of Paper: An Introduction. USA: TAPPI PRESS

Breede, M. H. (1999). Handbook of Graphic Arts equations. USA: GATFPress

Bureau, W. H. (1968). From Pulp to Paper. USA: Graphic Arts Publication Corp.

Choi, D., Echt, E., Gast, J. Niskanen, K., & Tattari, H. (2001). Functional additives can improve newsprint
         pressroom runability. Pulp & Paper, 75, 59-62.

Field, G. G. (1999) Colour and its reproduction (2nd Ed). Pittsburgh: GATFPress

Wilson, L. A. (1998). What the printer should know about paper (3rd Ed). USA: GATFPress




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