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					Computer Assisted Publishing
Institute for International Studies Ramkhamhaeng University Course: JR 103; October 2009

Images sources: Google

#3

Color / Colour
The US spelling, which excludes the “u”, was chosen to conform to the word's Latin origin, and to make all derivatives consistent colorimeter, colorize, colorless, etc). Elsewhere in the English-speaking world, the “u” has been retained.

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The word COLOR comes from Old Latin “coloris” or “colos” meaning: "a covering" (similar to celare "to hide, conceal"). In1225, the Old French word “couleur” appeared. Old English words for "color" were hiw (Hue = colornuances) and bleo. “Colors” as "flag of a regiment or ship" is dated 1590. “Color-blind” was first recorded 1844. “Colorful” as in "interesting" first appeared 1889. “Colored” in reference to "non-white skin" dates from 1611. “Coloring book” was actually invented in 1931.

What is Color?
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Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors (cone cells) in the retina. Only features of the composition of light that are detectable by humans (wavelength spectrum from 400 nm to 700 nm, roughly) are included to our understanding of color. Our brain takes into account the whitest and the blackest points and the gamut is subject to continuous adjustment. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra. Interestingly, some colors such as fluorescent and metallic cannot be fully sensed by the cone cells. Knowledge of an object’s identity, play their part in the sensation of “seeing” those colors.
textbook page 135

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What is Color?
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Because perception of color stems from the varying sensitivity of different types of cone cells to different parts of the spectrum - colors may be defined and quantified by the degree to which they stimulate those cells. These physical or psychological quantifications of color, do not fully explain the psychophysical perception of color appearance and because everyone's brain is unique, color perception is highly subjective.
The science of color is sometimes called chromatics. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as Light).
textbook page 135

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Color is….. .....reflected light
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Most of the light that reaches our eyes start off as white. When it strikes an object, the object’s surface absorbs certain ranges of wavelengths and reflects others. This subtraction of wavelengths produces the appearance of different colors. Pigment manufacturers assume the source light will be white, or of roughly equal intensity across the spectrum. If the light is not a pure white source (as in the case of nearly all forms of artificial lighting), the resulting spectrum will appear a slightly different color. Red paint for example, viewed under blue light, may appear black. Red paint is red because it reflects only the red components of the spectrum. Blue light, containing none of these, will create no reflection from red paint, creating the appearance of black.

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textbook page 135

Chromatic wheels
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A color wheel (also referred to as a color circle) is a visual representation of colors arranged according to their chromatic relationship.
RYB (red, yellow, and blue) is a historical set of subtractive primary colors and make up the primary triad in a standard color wheel the secondary colors VOG (violet, orange, and green) make up another triad. Complementary colors are lying opposite to each other.

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Goethe’s Color-Wheel
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Goethe's Theory of Colors (1810) provided the first systematic study of the physiological effects of color.
Red and Orange are lively, dynamic and ambitious Yellow is glorious and noble and gives the impression of warmth and comfort.
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Goethe assigned these colors to the “positive-side”

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Colors of the “negative-side” represent uneasy, cold, turbulent, longing for something and soft feelings.

Itten’s Color-Wheel
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Johannes Itten was one of the first to define and identify strategies for successful color combinations. (Bauhaus 1961)
Through his research he devised seven methodologies for coordinating colors - utilizing the hue's contrasting properties. These contrasts add other variations with respect to the intensity of the respective hues; i.e. contrasts may be obtained due to light, moderate, or dark value.

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Temperature of Light
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Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, and other fields.
The color temperature of a light source is determined by comparing its chromaticity with that of an ideal blackbody-radiator. The temperature is usually measured in Kelvin (K). When an object is heated to increasing temperatures, it emits light ranging from red, orange, yellow, over white to blue. It is the direct relationship between the temperature of an incandescent object and the color of the light it gives off - that enables light to be described in temperature.
textbook page 136

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Temperature of Light
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Yellow-red colors are considered warm Blue-green colors are considered cool. Higher Kelvin temperatures (3600–5500 K) are considered cool. Lower color temperatures (2700–3000 K) are considered warm.

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Cool light produces higher contrast and is considered better for visual tasks.
Warm light is preferred for living spaces because it is considered more flattering to skin tones and clothing. Color temperatures in the 2700–3600 K range is recommended for most general indoor and task lighting . The White point of a monitor is usually set to 5000 K to mach optimum conditions for artwork
textbook page 136

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Temperature of Light

Color Gamut
Spectral composition of visible light
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In DTP color-reproduction, the gamut is a complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a certain output device. Another sense refers to the complete set of colors found within an image at a given time. In this context, digitizing a photograph, converting a digitized image to a different color space, or outputting it to a given medium using a certain output device generally alters its gamut, in the sense that some of the colors in the original are lost or shifted in the process.
textbook page 136

Color Gamut

Textbook Page: 136

Mixing Colors
In DTP - Colors are mixed in two ways:
1. Based on light, known as additive color and is employed by cameras, scanners and monitors. (RGB) 2. Based on inks, known as subtractive color and is employed by printing devices. (CMYK, HSB, Spot, etc)

textbook page 136

Color Spaces
Greyscale and Duotone
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Monochrome images like scans of black and white photographs consist of a single greyscale channel with pixels at maximum strength printing solid black and minimum strength = white Intervening values give 254 levels of grey. Duotones are essentially greyscale images printed in two colors with one color usually being black

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Color Spaces
RGB
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RGB uses additive color mixing, because it describes what kind of light needs to be emitted to produce a given color. Light is added together to create form from out of the darkness. RGB stores individual values for red, green and blue. RGBA is RGB with an additional channel, alpha, to indicate transparency. Common color spaces based on the RGB model include sRGB, Adobe RGB and Adobe Wide Gamut RGB. Computer devices which use light as a medium employ the RGB system. It is an additive system with its three colors at full strength producing White and minimum level produces Black. Equal strength produces Grey.

Color Spaces
CMYK
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CMYK uses subtractive color mixing used in the printing process, because it describes what kind of inks need to be applied so the light reflected from the substrate and through the inks produces a given color. One starts with a white substrate (canvas, page, etc), and uses ink to subtract color from white to create an image. CMYK stores ink values for cyan, magenta, yellow and black. Cyan, Magenta, Yellow at medium strength producing near Black and all four colors at minimum strength leaving white. Black - the “Key”-color is included in the model to provide a deep black, not attainable by the colors alone, because of impurity of inks.

Color Spaces
HSB
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Hue – spectral color: red, green, yellow…. Saturation intensity or purity the extent to which it is grayed ( from over rich colors to nearly colorless Brightness ranging from very light to very dark

Color Spaces
Multi Color Spaces
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By involving 6 or more colors Hi-Fi color spaces such as Hexachrome give a much wider color gamut then CMYK. The colors Orange and Green are added to CMYK = CMYKOG By combining the Hexachrome-colors: cyan-magenta-yellow-black-orange-green 90% of the Pantone color range can theoretically be matched (in CMYK = > 30%)

textbook page 138

Check colors @: wikipedia.org/wiki/List_of_colors

Working with Color Spaces
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Generally CMYK, Hexachrome or Spot Colors are used in professional printing. They can be split (separated) into their component colors to create film separations for each ink. Image enhancement should always be completed in RGB before being converted to CMYK because: RGB-files are ¾ of the CMYK size RGB images have a broader gamut so there is more information available for enhancing RGB images can be used for other purposes like the world wide web.
textbook page 139

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Working with Color Spaces
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Images should be specified as CMYK before imported into a print project, because their colors will be added to the color palette of the layout-program they are imported to. In offset printing, a spot color is any ink (pure or mixed) other than one of the four process colors, cyan, magenta, yellow and black. Spot colors usually give a good color fidelity, because for each spot color created, there will be a special film in the printing process
textbook page 139

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Adding color to your document
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You can either add color to your document by applying color to graphic elements and type - or by importing colored bitmap and vector images. (Remember to convert bitmap, etc. to CMYK or spot colors. Colors applied to type and graphics can be mixed using the color palette or chosen from a color system like Pantone or HKS. CMYK enables you to an almost limitless number of colors – and are compatible to most printing machines.

You should always talk to the printer before choosing the color space to guarantee best compatibility between your work and the outcome.
textbook page 140

“Kuler”
a color- generator by Adobe

Maintaining Color Fidelity
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ICC (International Color Consortium) and ICM International Color Management) have established standards for color profiles Color Management Systems provide those standard values in terms of consistency and predictability CMSs are used to calibrate individual devices and manage the color space conversion of images. External devices such as offset litho printing presses are pre-calibrated by CMS programs and supplied as ready made ICC/ICM profiles

textbook page 140

Color Management
Steps that need to be taken for Color Management are as follows:
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Obtain ICC/ICM profiles of external devices Calibrate each device by profiling them – scanner-monitor-digital printer – Use the profiles when scanning, viewing and outputting documents.

textbook page 141

Color Management
Calibrating Devices
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Scanners are calibrated by scanning specially prepared color swatches and comparing the results to ideal values in a digital image of the swatches supplied.
Monitors are calibrated by measuring screen output using a colorimeter or spectrophometer and comparing the results to ideal values. If no colorimeter is available monitor data is entered in dialog boxes (preferences) based on the monitors specs.

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Digital printers and printing presses are calibrated by printing color swatches on each device. The outcome is measured by using colorimeters
textbook page 141

Using the Profiles
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When images are scanned, documents are viewed and printed – the profiles you have created should be referred to - in order to achieve and maintain color accuracy and consistency (Proofing) When scanning to RGB assign a profile for scanner and monitor , when converting to CMYK, assign a further profile this time for the outputting device. Proofing devices should imitate the final printing press in which case the printing press profile should be used. Profiles are selected within the scanning control, the monitor settings and mode conversion programs provided they are conform to the ICC standards. In case of Photoshop, which has it’s own settings, profiles are selected within the color setting control.

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Favourite Colors (survey of 1888 people)
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1% 2% 2% 3% 3%

Grey Brown Gold Violet White

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5% 5% 8% 12 % 20 % 38 %

Yellow Pink Black Green Red Blue

Blue
Unrestricted Dimension Divine Faithfulness Cold Blue Monday The Blues Masculine

Red
Love and Hate Blood and Vitality Aggressiveness Dynamic Proximity Communism The Forbidden

Green
Nature Color of Life Hope Youth Islam Middle distant Poison

Black
The End Painting Black Elegance Power Individuality Magic Objectiveness

Pink
Tenderness Feminity Romance Sweetness Easiness Naivete´ Youth

Yellow
Sun and Optimism Gold Alert Ideal Distance Asian Emperors Outlaws Envy and Egoism

Activity

Energy

Power

Trust

Loveliness