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Influence of Weave on Colour Values of Woven Fabrics

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Influence of Weave on Colour Values of Woven Fabrics Powered By Docstoc
					1. Introduction

A specific property of fabrics made of differently coloured threads is that the colour
values of surface are not influenced only by the colour values of individual
components – threads and their number but also by a fabric constructional parameters
such as the warp and weft threads fineness, density and weave. With analytical
estimation of the influence of the threads fineness and density, coupled with
equations for determining colour differences in the CIE L*a*b* colour space (Mc
Donald, 1997), the fractions of individual colour components in a colour repeat can
be determined relatively precisely and on that basis also its colour values. But the fact
is that in such calculations, except in the number of the warp and weft interlacing
points, a weave with its specifies never appears. In other words, with the same
number of the warp and weft interlacing points in a colour repeat, the same colour
values are always obtained by calculation, despite different weaves and visible colour
differences. In practise the surface effect of different weaves has always been
evaluated visually, without further objective measurement. Such estimations were
made on the basis of subjective preference and in consequence there were frequent
misunderstandings about colour effect. The contribution of the paper is the
verification of theoretical calculations of colour values on different weaves and the
estimation of deviations between calculated and spectrophotometrically determined
colour values. The researches will try to find out how can different disposition and
agglomeration of interlacing points on woven structure influence on
sectrophotometrically determined colour values. Moreover the connection between
constructional parameters (threads density and fineness) and the weave will be
detailed analysed with a purpose to put light on the possibilities of colour control of
woven fabrics with a help of constructional parameters and thread colours.

2. Theoretical part

2.1 Colour Deviation
The CIE L*a*b* colour space defines the value of a colour deviation between a
pattern and a selected standard through the E*ab values. Their relation with L*, a*
and b* colour values is presented in Equations 1 and 2 (Nassau, 1998).
                    E *ab  a *  b *  L *
                                   2        2        2
                                                                                 (1)
                  E *ab    L *2  Cab *2  H ab *2                        (2)
Where:
 a* is the difference in the a* (red – green) value between the pattern and        the
  standard and b* is the difference in the b* (yellow – blue) value between         the
  pattern and the standard;
 L* is the difference in the L* (lightness) value between the pattern and          the
  standard;
 C*ab is the difference in the C*ab (chroma) value between the pattern and         the
  standard and C*ab = ((a*)2 + (b*)2)1/2;
 H*ab is the difference in the H*ab (hue) value between the pattern and the
  standard, where H*ab = C*ab hab( /180) and hab=arc tg*(b*/a*);
 E*ab is the colour difference between the pattern and the standard.

Colour deviation in the mentioned system means the shortest distance in the CIE
L*a*b* co-ordinate space from the position of a certain colour to the position of the
standard colour which it is compared to. Most common comparisons in practice are
made between the obtained colour and the colour required and evaluated through
colour values by customer.
                                             white   L*
                                                                      b*
                                                          S   E*ab        yellow

                                                                       P
                   -a*                         L*

                 green                                b*       H*ab

                                                               C*ab

                                                      a*
                                                                                      a*
                                                                                    red



                              -b*
                                    blue
                                                     black


Fig. 1. CIE L*a*b* colour space and colour difference between colour P and standard
colour S.

The first question that arises in the case of fabrics made of differently coloured
threads which differ in weave only is which colour value is to be taken as a reference
for determination of colour deviations.

The colour deviation between the woven fabric made of differently coloured threads
and the woven fabric with standard colour values can be calculated as:
                                      2                         2                              2
             n
                    a *i U i   a *s    b *i U i   b *s    L *i U i   L *s 
                                               n                         n
  E *ab                                                                                   (3)
              i 1                        i 1                    i 1                
Where:
 Ui - the fraction of i colour component in the entire colour repeat (Dimitrovski &
  Gabrijelčič, 2001);
 a*i, b*i and L*i - the colour values of i component of woven fabric;
 a*s, b*s and L*s - the colour values of standard woven fabric;
 E*ab - the colour difference between two woven fabrics;
 n number of colour components;
 i - colour component.
2.2 Basic Weaves and Geometrical Arrangement of Their Interlacing Points
Plain weave is the simplest and the most common weave with the smallest repeat
unit. It is characterised by the tightest and maximally possible interlacing of the warp
and weft threads. All other weaves have reduced interlacing of the warp and weft
threads and larger repeat units. In these weaves the agglomeration of warp and weft
interlacing points increases the size of colour surfaces.

Different configuration of the warp and weft interlacing points in plain weave and
similar weaves as well as the increase of the weave repeat and the colour repeat are
presented in Fig.2.
In plain weave (a) four warp interlacing points surround one weft interlacing point, in
rep 2/4 weave (b) three warp and one weft interlacing point surround a single weft
points, while in basket 4/4 a weft point is surrounded by two weft and two warp
interlacing points.
It is evident that the specificity of a weave leads to agglomeration of the same type
interlacing points and, consequently, to increase of the size of individual colour
surfaces and their relocation – grouping into a narrow areas with prevailing surfaces
of one colour (Božič, 2002).


                 a                       b                    c




Fig. 2. Schematic presentation of weaves with different size of repeat and
agglomeration: a – plain, b – rep 2/4 and c – basket 4/4.

The warp and weft interlacing point is made up of three different colour components:
warp thread, weft thread and the space between threads, which all contribute to the
colour values of a final fabric (Gabrijelčič & Dimitrovski, 2002).

Colour values of colour repeat in the weave can be calculated if taking in
consideration colour values of its colour components (warp, weft and space between
threads) and constructional parameters of woven structure (threads diameter and warp
and weft density). Every single component in one repeat has its surface, which size
and shape depend on threads diameter and density. The characteristics of components
surface change with a change of constructional parameters. As a consequence the
influence of single colour component on colour values of surface of woven fabrics is
more or less perceivable.
3. Experimental part

Computer simulations of seven different weaves are prepared by using the Arahne
CAD system (Arahne, 2002). All weaves were chosen with the same ratio between
the number of warp and weft interlacing points on the face side and identical
constructional parameters: plain, rep 2/4, rep 2/8, twill 4/4, basket 4/4, twill 8/8 and
basket 8/8. Weave patterns are shown on the Fig. 3.

     1              2          3             4             5            6            7
   plain         rep 2/4    rep 2/8      twill 4/4     basket 4/4   twill 8/8    basket 8/8




Fig. 3. Patterns of plain, rep 2/4, rep 2/8, twill 4/4, basket 4/4, twill 8/8 and basket 8/8
weaves.

The warp threads are red, weft threads are yellow and the foundation is white with
L*, a*, b*, C*ab and hab colour values given in Table 1.

   Colour value              Warp-red                Weft-yellow       Foundation-white

        L*                             47,18                  84,71                  94,16
         a*                            57,65                  -7,29                   4,14
         b*                            17,49                  69,69                 -11,20
        C*ab                           60,24                  70,07                  11,94
       hab ()                         16,87                  95,97                 290,29

Table 1. Measured L*, a*, b* and calculated C*ab, hab colour values of red warp
thread, yellow weft thread and white foundation.

The simulations had constant warp and weft thread fineness 30 tex. Density was
variable, from initial 30 threads/cm with the reduction of 10 % to 27, 24 and 21
threads/cm.

The fractions of individual threads and of foundation reflectance were determined by
calculation on the basis of constructional parameters (Gabrijelčič & Dimitrovski,
2002), which are presented in Table 2 and schematically on Fig. 4. Where go and gw is
the density of warp and weft threads (threads/cm), d o and dw is the diameter of warp
and weft threads (mm) and Uo, Uw, Uf are the fractions of warp and weft threads and
of the space between threads.
With the help of colour values of warp and weft threads and fractions of colour
component (Uo, Uw, Uf) the theoretical colour values L*, a*, b*, C* ab and hab of
different weaves were calculated (Gabrijelčič & Dimitrovski, 2001), (Bregar, 2002),
(Kožuh, 2002), (Kysselef, 2002).

Colour values of the obtained surfaces were measured with the Spectrolino
SpectroScan spectrophotometer of GretagMacbeth. Light source was D65.

                                Constructional parameters
Patterns                Warp                                      Weft             Fund.
              go        do             Uo               gw        dw       Uw       Uf

  1-7              30   0,304          0,496                 30    0,304   0,496    0,007
  1-7              27   0,304          0,484                 27    0,304   0,484    0,032
  1-7              24   0,304          0,463                 24    0,304   0,463    0,073
  1-7              21   0,304          0,435                 21    0,304   0,435    0,131

Table 2. Constructional parameters of fabric and calculated fractions of the warp and
weft threads and the space between the threads (foundation) for pattern 1 to 7.

                                        warp

                           weft


                                            1       3
                                                2                 1/gw
                           1/go




                                   3
                            1
                                   2        dw

                           do


Fig. 4. Schematically presentation of the density of warp and weft threads (go, gw) and
warp and weft diameter (do, dw).

Finally, colour differences E*ab were defined by means of Equations (1), (2) and
(3):
- between plain weave taken as standard and other weaves;
- between theoretically calculated and measured colour values of the patterns in
   different weaves.
4. Measurements and results

Calculated and measured colour values L*, a*, b*, hab and C*ab of patterns are
presented in Table 3 and Fig. 5, 6, 7 and 8 at varying densities 30, 27, 24 and 21 warp
and weft threads/cm, where index m means the measured (capital characters) and
index t theoretically calculated values (small characters).
Theoeretical calculated colour values are the same for all weaves, because there is the
same ratio between the number of warp and weft interlacing points in colour repeat.

Plain is pattern 1, rep 2/4 is pattern 2, rep 2/8 pattern 3, twill pattern 4/4 pattern 4,
basket 4/4 pattern 5, twill 8/8 pattern 6 and basket 8/8 pattern 7.

                                                         Measured
           Col.      Calcula
 Density   value       ted     Plain   Rep 2/2 Rep 2/8     Twill    Basket   Twill   Basket
                                                            4/4      4/4      8/8     8/8
                      1-7       1        2        3         4         5       6        7

           L*         66,15    61,97    62,00   62,15      63,04    63,69    64,79   65,93
           a*         25,01    30,31    29,14   27,43      26,27    26,19    25,03   22,37
   30      b*         43,15    36,69    37,71   38,50      40,09    40,16    42,05   43,88
           hab ()    59,90    50,44    52,30   54,53      56,77    56,89    59,24   62,99
           C*ab       49,87    47,59    47,66   47,27      47,93    47,95    48,94   49,26

           L*         67,86    63,36    63,26   63,06      64,80    63,73    65,35   63,92
           a*         24,41    28,16    29,08   28,26      25,68    27,36    24,82   26,19
   27      b*         42,67    37,02    37,69   37,42      39,45    38,27    40,48   38,51
           hab ()    60,23    52,74    52,34   52,94      56,93    54,44    58,49   55,78
           C*ab       49,16    46,51    47,60   46,90      47,07    47,04    47,48   46,57

           L*         67,93    64,70    64,27   63,81      64,79    65,04    64,89   65,08
           a*         23,61    26,09    26,80   25,63      23,93    25,73    24,21   24,38
   24      b*         39,55    36,90    35,87   36,14      38,36    36,91    37,86   37,66
           hab ()    59,16    54,74    53,24   54,66      58,05    55,12    57,41   57,08
           C*ab       46,06    45,19    44,78   44,31      45,21    44,99    44,94   44,87

           L*         69,70    66,47    66,55   66,43      66,25    66,39    66,09   67,29
           a*         22,44    23,63    24,33   23,03      23,45    24,08    23,95   21,87
   21      b*         36,45    32,89    33,62   33,11      34,23    33,54    33,85   34,86
           hab ()    58,17    54,31    54,11   55,19      55,58    54,33    54,72   57,90
           C*ab       42,80    40,50    41,50   40,33      41,49    41,29    41,46   41,15

Table 3. Measured and calculated colour values L*, a*, b*, hab () and C*ab of the
patterns in different weaves 1-7 and warp and weft densities 30, 27, 24 and 21
threads/cm.
                                                             L*m             L*t                      a*m            a*t           b*m
                                                             b*t             hm                       ht             C*m           C*t
                                      70
                                      65
                                      60
                                      55



                  Color values
                                      50
                                      45
                                      40
                                      35
                                      30
                                      25
                                      20
                                                     1               2         3              4              5             6       7
                                                                                   Patterns


Fig. 5. Curves of measured and theoretically determined colour values L*, a*, b*, h ab
and C*ab for the weaves 1 to 7 at the warp and weft threads density 30 threads per cm.


                                                             L*m             L*t                  a*m                a*t           b*m
                                                             b*t             hm                   ht                 C*m           C*t
                                 80

                                 70

                                 60
                  Color values




                                 50

                                 40

                                 30

                                 20
                                                     1               2        3               4              5             6       7
                                                                                   Patterns


Fig. 6. Curves of measured and theoretically determined colour values L*, a*, b*, hab
and C*ab for the weaves 1 to 7 at the warp and weft threads density 27 threads per cm.

                                                               L*m             L*t                     a*m             a*t             b*m
                                                               b*t             hm                      ht              C*m             C*t
                                                80

                                                70

                                                60
                                 Color values




                                                50

                                                40

                                                30

                                                20
                                                         1               2         3              4              5             6       7
                                                                                       Patterns

Fig. 7. Curves of measured and theoretically determined colour values L*, a*, b*, h ab
and C*ab for the weaves 1 to 7 at the warp and weft threads density 24 threads per cm.
                                          L*m       L*t                  a*m       a*t       b*m
                                          b*t       hm                   ht        C*m       C*t
                                 80

                                 70

                                 60


                  Color values
                                 50

                                 40

                                 30

                                 20
                                      1         2    3               4         5         6   7
                                                          Patterns

Fig. 8. Curves of measured and theoretically determined colour values L*, a*, b*, h ab
and C*ab for the weaves 1 to 7 at the warp and weft threads density 21 threads per cm.

The results of colour differences E*ab between different weaves given in Table 4
and Fig. 9. Plain weave is taken as standard woven structure and its colour
differences are 0,00, other differences are calculated with Equations (1) and (2).

E*ab                                       Patterns
Weave       Plain       Rep       Rep       Twill       Basket     Twill     Basket
                         2/4      2/8         4/4         4/4       8/8       8/8
Density       1           2        3           4           5         6          7
  30/30         0,00       1,55     3,41         5,39        5,65     8,03      11,42
  27/27         0,00       1,14     0,51         3,76        1,53     5,20        2,53
  24/24         0,00       1,32     1,26         2,61        0,49     2,12        1,91
  21/21         0,00       1,01     0,64         1,37        0,79     1,08        2,77
Table 4. Colour differences of weaves 2, 3, 4, 5, 6 and 7 in comparison with a
standard fabric in plain weave-1 at densities 30, 27, 24 and 21 threads per cm.




Fig. 9. Curves of colour differences E*ab of weaves 2, 3, 4, 5, 6 and 7 in comparison
with a standard fabric in plain weave-1 at densities 30, 27, 24 and 21 threads per cm.
The results of colour differences E*ab between theoretically calculated and
spectrophotometrically determined colour values for all weaves 1-7 at densities 30,
27, 24 and 21 threads per cm are given in the Table 5.

    E*ab                                          Density (go/gw)
    Weave                      30/30           27/27      24/24                    21/21       Average E*ab

Plain                   9,34         8,14          4,86        4,95          6,82
Rep 2/4                 7,99         8,23          6,09        4,64          6,74
Rep 2/8                 6,59         8,09          5,72        4,71          6,28
Twill 4/4               4,54         8,14          3,37        4,23          5,07
Basket 4/4              4,05         4,62          4,45        4,70          4,46
Twill 8/8               1,75         6,72          3,53        4,70          4,17
Basket 8/8              2,75         3,36          3,51        2,94          3,14
Average E*ab           5,29         6,76          4,50        4,41
Table 5. Colour differences E*ab between calculated and measured colour values of
weaves 1, 2, 3, 4, 5, 6 and 7 at densities 30, 27, 24 and 21 threads per cm.

On Fig. 10 the graphic presentation of differences between theoretically calculated
and spectrophotometrically determined colour values of different weaves by threads
density 30, 27, 24 and 21 threads/cm are presented.
                                   plain              rep 2/4               rep 2/8        twill 4/4
                                   basket 4/4         twill 8/8             basket 8/8
                         10
                          9
                          8
                          7
                E*ab values




                          6
                          5
                          4
                          3
                          2
                          1
                          0
                                       30/30            27/27                24/24         21/21

                                                                  Thread density

Fig. 10. Curves of colour differences E*ab between calculated and measured colour
values of weaves 1, 2, 3, 4, 5, 6 and 7 at densities 30, 27, 24 and 21 threads per cm.

5. Disscusion

5.1 Influence of weave on colour values at different densities
In Fig. 5, 6, 7 and 8 presenting the curves of the calculated and measured colour
values of simulations in different weaves at density 30, 27, 24 and 21 threads per cm,
it is evident that the colour values L*, a*, b*, h ab and C*ab change differently with the
change of the weave from plain (pattern 1) through rep 2/4 and 2/8 (patterns 2 and 3)
to twill 4/4, basket 4/4 (patterns 4 and 5) and twill 8/8, basket 8/8 (patterns 6 and 7).
It can be observed, that influence of weave depends on warp and weft thread density.
The biggest change of colour values is at thread density go=gw=30 /cm (Fig. 5), where
curves of L*, a*, b* and hab indicate different but considerable changes in colour
values.

 Density 30/30
Lightness L* of the patterns at density 30 threads per cm increases from the pattern 1
(plain) to the pattern 7 (basket 8/8). The simulations in basket 4/4 weave are
substantially lighter in view of twill 4/4 and rep 2/4 weave, even if on the surface of
the same size, there are the same number of warp and weft interlacing points. Similar
is with weaves basket 8/8, twill 8/8 and rep 2/8. Different arrangement and
agglomeration of interlacing points influence in different way on colour values of
surfaces. Lightness L* increases due to increase of the colour repeat surface (threads
agglomeration on the simulation surface), the result of which are outstanding yellow
weft threads which have higher lightness (L*yell =84,71, L*red = 47,18). Gradation of
the colour value b* and decrease of the parameter a* from plain weave to basket 8/8
weave can be explained accordingly. Namely, the colour values b* of yellow weft
threads (b* yell = 69,69) are higher than the colour values a* of red warp threads
which contain a small portion of yellow colour (a* red = 57,65, b* red = 17,49). The
consequence is a considerable change of the colour hue hab, which is 50,44 in plain
weave and even 62,99 in basket 8/8 weave (Table 3). On the contrary, the chroma of
all simulations in all weaves remains practically unchanged due to equal ratio of the
values b* and a* in all weaves (Equation 2). In weaves twill 8/8 and basket 8/8
chroma is increased, what is the consequence of points grouping on the surface.

  Densities 27/27, 24/24, 21/21
Similar results are obtained in simulations of the warp and weft density 27 threads
per cm, however, in simulations of the warp and weft density 24 and 21 threads per
cm the situation is completely different. Colour differences between simulations of
different weaves are small at low densities (Table 2). The fractions pertaining to the
surfaces of the warp and weft threads and to the space between the threads in an
individual colour repeat are presented in Table 1. When the densities are low, the
effect of the foundation reflectance on colour values is small. At density 30 threads
per cm the space between the threads occupies 0,78 % of the entire surface (U f) and
at density 27 threads per cm 3,2 %, which has minimum effect on the colour values
of the fabric surface. On the other hand, the surfaces of the warp and weft threads by
occupying 49,6% at density 30 and 48,4% at density 27 (U o and Uw) have
considerable effect on colour values of the fabric surface. At lower densities the
influence of the reflectance of the foundation and of the threads in bottom layers of
the fabric on the colour values of simulations considerably increases due to the 7.31
% fraction of foundation at density 24 threads per cm and 13,1 % fraction of
foundation at density 21 threads per cm. These fractions are high and white colour of
space between threads affects the colour effect of warp and weft threads on the
surface. Grouping and agglomeration of interlacing points at low densities don’t have
such a role in determination of colour values of woven structure.

5.2 Colour deviations E*ab between different weaves
Colour differences between the weave, which was taken as standard – plain and other
weaves, are given in Table 4 and on Fig. 9. The curves on Fig. 9 show the important
difference between higher densities 30 and 27 threads/cm and lower densities 24 and
21 threads/cm. The curve of density 30 increases from initial E*ab value of 1,55 by
rep 2/4 weave to final 11,42 by basket 8/8 weave. In the case of density 27 the curve
is variable. It seems that twill weaves play different role in colour changing in
comparison with plain weave. Pattern 4-twill 4/4 and pattern 6-twill 8/8 have higher
colour deviation as other weaves. Twill 4/4 has E*ab value 3,76 and twill 8/8 value
5,20. The reason for this phenomenon can be found out in typical disposition of
interlacing points on the surface. By twill weave warp and weft interlacing points are
not grouped in square groups as by other weaves and the disposition of points is
graduated (Fig. 3). Likewise, the colour deviations of twill weave are higher at
density 24 threads/cm (2,61 by twill 4/4 and 2,12 by weave 8/8) but not so obviously
as at density 27. At thread density 21, E*ab values between colour values of standard
plain weave and other weaves are low around value 1, except weave basket 8/8,
where value of colour difference is 2,77. At this low density the influence of white
foundation reflectance and threads in lower layer is high and the agglomeration and
different disposition of points don’t affect the colour of surface. Colour deviations
between different weaves are minimal.

5.3 Deviations between theoretically calculated and measured colour values
The calculated colour values of individual colour at all weaves are constant at the
same density and presented in diagrams (Fig. 5, 6, 7 and 8) as straight hatched lines.
With their help the deviations between the calculated and the measured values at
different densities can be analysed (Table 5). Equal calculated colour values of all
weaves are the result of the same ratio between the number of warp and weft
interlacing points.
At higher densities (30 and 27 threads per cm) the deviations between the calculated
and the measured values are bigger than at lower densities (24 and 21 threads per
cm). The curves of measured L*, hab, a* and b* values in Fig. 5 considerable differ
from calculated values in weaves plain-1, rep 2/4-2, and rep 2/8-3. But in weaves
twill 4/4-4, basket 4/4-5, twill 8/8-6 and basket 8/8-7 the curves of measured values
approach the lines of calculated and at density 30 threads/cm in weaves 6 and 7 they
cross them. At densities 27, 24 and 21 the measured values are more constant in
different weaves and closer to the lines of calculated values. At lower densities the
colour values of woven structure can be better predicted.
If we compare the curves on the Fig. 5, 6, 7 and 8 it can be noticed, that measured
colour values are in generally lower than calculated, except value a*, where measured
values are higher than calculated. The theoretical prediction of colour values gives us
higher values as spectrophotometrical determined. Reason for that should be found in
equations for calculations of colour values.
Moreover, the highest deviation is observed in the values L* and h ab (a*, b*), whilst
in the value C*ab there is almost no difference between the calculated and the
measured values. So, the values of chroma C* ab can be better predicted in comparison
with other colour values.
In Table 5 and Fig. 10 are compared E*ab values between calculated and measured
colour values for all weaves in densities 30/30, 27/27, 24/24 and 21/21. It can be
noticed, that E*ab values differ from weave to weave at density 30, but at densities
27, 24 and 21 they come closer to each other. Different kinds of weaves behave
differently at changing density. The curves of rep 2/4 and 2/8 are similar and the
same can be observed by curves of twill 4/4 and 8/8 and basket 4/4 and 8/8.
Moreover, we can see similar behaviour of weaves plain, rep and twill, where E*ab
values are changeable at different densities. They are similar at density 27 and 21, but
different at densities 30 and 24. Particular behaviour have weaves of basket 4/4 and
basket 8/8, where E*ab values at different densities are very similar and in generally
lower in comparison with other weaves.

6. Conclusions

The influence of different fabric weaves on colour values of the fabric simulations is
investigated in the experimental work. It is found out that by agglomeration of
threads on the fabric surface, i.e. by increasing individual colour areas in a particular
colour repeat (threads grouping), the colour values L*, a*, b*, h ab and C*ab change
differently in dependence on the colour of the warp and weft threads and the fabric
density. At higher densities with a minimum percentage of reflectance, the changes of
colour values are more pronounced. At density 30 warp and weft threads/cm the
values L*, a* b* and hab change from 4 (L*) to 12 (hab) units, while at densities 24
and 21 it can be seen minimal influence of weave. At lower densities where
reflectance occupies more than 10 % of the repeat surface, the change of weave has
no significant influence upon colour values.
Resemblance can be seen in colour deviations between standard weave plain and
other weaves, where E*ab values are increasing rapidly at density 30 threads/cm,
while at lower density 24 and 21 lower deviations can be observed. Twill weaves
show particular behaviour at densities 24 and 27, while they have unusual higher
E*ab values in comparison with other weaves. By lower densities the foundation
reflectance has more influence on colour values of surface and the differences
between different weaves are higher. Predicted colour values of weaves with the
same relation between number of warp and weft interlacing points are the same,
although the constructions of these weaves are very different. The comparison of
E*ab values between calculated and measured colour values at changing density
indicates that in some weaves at certain density colour values can be better
theoretically predicted. By basket weaves can be the colour values well predicted
irrespective of density, while by other weaves the prediction depends on density.
7. Further researches

During further researches in this field the exact limit of the threads density at which
reflectance gets a deciding influence upon the fabric colour values could be defined,
and the influence of the size of individual colour areas in a weave repeat upon its
value precisely analysed. The research could be enlarged on other weaves too and
detailed investigation of increasing or decreasing, grouping and agglomeration of
interlacing points should be done. Consequently, this would provide analysis of
deviations between the calculated – theoretically and spectrophotometrically
determined colour values and of the reason for such deviations. Accordingly, the
experimental work could further extend to the determination of the influence of other
constructional parameters (the threads fineness and the interdependence of several
constructional parameters; density, fineness, weave) upon colour values of fabrics
and to the analysis of colour deviations at variation of certain constructional
parameters which would still provide achievement of desired colour values.

8. References

Arah Weave 3.2 User’s Manual 1993-2002 Arahne. Available from:
   http//www.arahne.si Accessed: 2003 -01-15
Božič, P. (2002). Vpliv vezave na barvne vrednosti tkanin iz različno obarvanih niti,
   Diplomsko delo, Univerza v Ljubljani, Naravoslovno tehnična fakulteta, Oddelek
   za tekstilstvo, Ljubljana
Bregar, N. (2002). Vpliv finosti na barvne vrednosti tkanin iz različno obarvanih niti,
   Diplomsko delo, Univerza v Ljubljani, Naravoslovno tehnična fakulteta, Oddelek
   za tekstilstvo, Ljubljana
Dimitrovski, K. & Gabrijelčič, H (2001). Izračunavanje i mjerenje boja tkanina iz
   različito obojenih niti, Tekstil, Vol. 50, No. 11, November 2001, pp. 558-567
Dimitrovski, K & Gabrijelčič, H. (2002). Napovedovanje barvnih vrednosti žakarskih
   tkanin = Predicting of colour values of jacquard fabrics. Tekstilec, Vol. 45, No.
   7/8, pp.179-194., ISSN 0351-3386
Gabrijelčič, H. & Dimitrovski, K.(2002). Values calculation of Woven Fabrics –
   Usage for Dyeing Mistakes and Corrections, In: DAAAM International Scientific
   Book 2002, B. Katalinic, (Ed), pp. 191-204, DAAAM International Vienna, ISBN
   3-901509-30-5, Vienna
Kožuh, M. (2002). Vpliv gostote in finosti na barvne vrednosti tkanin iz različno
   obarvanih niti, Diplomsko delo, Univerza v Ljubljani, Naravoslovno tehnična
   fakulteta, Oddelek za tekstilstvo, Ljubljana
Kysselef, I. (2002). Vpliv gostote na barvne vrednosti tkanin iz različno obarvanih
   niti, Diplomsko delo, Univerza v Ljubljani, Naravoslovno tehnična fakulteta,
   Oddelek za tekstilstvo, Ljubljana
Mc Donald, R. (1997). Colour Physic for Industry, Society of Dyers and Colourists
   Bradford, (2nd ed.), ISBN 0 90 1956 70 8, England
Nassau, K. (1998). Colour for science, art and technology, Elsevier Science B. V.,
   (Volume 1), ISBN 0 444 89846 8, Netherlands

				
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