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Color Models

Before understanding color models, it is essential to understand different systems. Many of us are aware of the colors as paints. Hence when we mix blue and yellow, we get the shade of green. But the result will be different if we mix green and red light. It will create yellow if 100% red and green light are mixed. So let us understand these two different properties. If we consider the colors produced by the monitor, the light beams generate it. It is based on the RGB model and it is additive color model. Then comes to paint or printing inks. This is based on CMYK model, which is subtractive color model.

RGB Model

Computer creates the colors based on RGB model. It produces spectrum of visible light. Monitor can create millions of colors by combining different percentages of three primaries, red, green and blue. While using the image processing software like Photoshop you can see that these RGB colors are added with the help of numerical value, which is between 0 to 255. With RGB, mixing of red and green equally gives yellow, mixing of green and blue creates cyan and the mixing of red and blue creates magenta. When all the three colors, red, green and blue are mixed equally they produces white light. Hence it is called Additive color model. Another RGB model based example is human eye itself and scanners.

The basic advantage of RGB model is; it is useful for full color editing because it has wide range of colors. But at the same time this model is said to device dependent. It means the way colors displayed on the screen depends on the hardware used to display it.

CMYK Model

Opposite model of RGB is CMY. Printing inks are based on this model. With the full presence of cyan, magenta and yellow we get black. But practically in the printing industry it is impossible to create black with these three colors. The result of the mixture of CMY is muddy brown due to the impurities of the printing inks. Hence black ink is added to get solid black. The outcome of this process CMYK model and k stand for black color, which is also recognized as 'key' color. Since black is a full presence of color, you will have to subtract the levels of cyan, magenta and yellow to produce the lighter colors. This can be explained in different way. When light falls on the green surface or green ink. It absorbs (subtracts) all the colors from light except green. Hence the model is called subtractive model. Print production is based on this model.

It is useful to have proper understanding of the color models. The monitors as well as scanner works on RGB principle. While scanning we can adjust the software to produce desired result. CMYK is for print industry. It cannot produce the color range of RGB hence after finishing the work on computer in RGB mode when you convert it into CMYK for printing some tonal changes can be occurred. In spite of its limitation CMYK model is considered as best model available for printing because it can produce properly finished output.