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Color Modes |
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There are a number of methods for generating and reproducing color. In Photoshop,
these methods are called "color modes," and the best known of these are RGB and CMY(K). |
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Color Mode 1: RGB
RGB stands for Red, Green and Blue, the primary exposure colors. Mixing
them together allows the creation of infinite colors. In digital photography, the concentration, or tone,
of each of these colors can be represented by one of 256 degrees, numbered from 0 to 255, with zero
meaning low concentration of a color, or that there is little or none of that color present, and 255 meaning
that the highest possible concentration of that color is present. These three colors have the property
of turning white if they are mixed when all at their maximum value of 255. Digital
cameras, monitors, and scanners are all examples of devices that use RGB for color reproduction. |
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*Color concentration is represented in 256 stages, from 0 to 255
*RGB is used by digital cameras, monitors, and scanners |
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*Color concentration is represented from 0 to 100%
*CMYK is used in ink-based color reproduction: painting, printing, desktop printers,
etc. |
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Color Mode 2: CMY(K)
Conversely, CMY stands for Cyan, Magenta and Yellow. And in contrast to RGB
being called the primary colors of light, CMY is referred to as the primary reflected colors, or
the primary colors of ink. Mixing these colors together enables the creation of numerous other colors. Their
concentrations, or tones, range from 0 to 100%, with zero meaning that a color is not present at all, and
100% meaning that the color is the color of the ink in question, in its purest form. These colors
have the property of creating black if they are combined when their values are all 100%. For this reason,
black ink (designated as K) is used to indicate black when created through the combination of CMY, hence
CMYK. Color generation methods using CMY theory are used in imaging methods based on ink, for example painting,
printing and making prints from digital photos. |
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Lab
Lab is another mode worth remembering. This scheme, promoted by CIE, the International Committee on Lighting, is a
standard for color in various industries, including engineering products. The "L" in Lab indicates
brightness in a range from 0 to 100, while the "a" gives color element values ranging from green to red, and the "b" from
blue to yellow.Lab colors define the entire spectrum that can be perceived by the naked eye. Its distinguishing characteristic
is that it can represent a wide range of colors, as shown by the opposite image.
The advantage of the Lab color scheme is that, when one wants to change the value, all one has to do is adjust the
brightness to change the color, as opposed to RGB or CMYK, in which one adjusts the value by changing all of the colors involved. When
sharpening an image, applying a sharpen filter for only the "L" channel minimizes image scattering.
While adjusting color in Lab mode is tricky, it is superior to the other modes
when it comes to retouching brightness levels. |
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