RGB Vs. CMYK

RGB is an additive type of colour mode, that combines the primary colors, red, green and blue, in various degrees to create a variety of different colours  When all three of the colors are combined and displayed to their full extent, the result is a pure white. When all three colors are combined to the lowest degree, or value, the result is black. CMYK is a four color mode that utilizes the colors cyan, magenta, yellow and black in various amounts to create all of the necessary colors when printing images. It is a subtractive process.

Converting RGB format pictures to CMYK mode for printing can be a complex task. It often involves using RGB to CMYK conversion tables, or various software utilities, to ensure that the colors seen on the computer screen will match the colors that appear on print. One way of making this process quicker and more efficient is to simply convert a file to CMYK format as soon as it is created if there are any future plans for converting the documents to printed format.

Subtractive Colors
Subtractive colors are seen when pigments in an object absorb certain wavelengths of white light while reflecting the rest. We see examples of this all around us. Any colored object, whether natural or man-made, absorbs some wavelengths of light and reflects or transmits others; the wavelengths left in the reflected/transmitted light make up the color we see.

This is the nature of color print production and cyan, magenta, and yellow, as used in four-color process printing, are considered to be the subtractive primaries. The subtractive color model in printing operates not only with CMY(K), but also with spot colors, that is, pre-mixed inks.

Red, Green, and Blue are the "additive colors " - combine red, green and blue light, and you get white light. Cyan, Magenta and Yellow are "subtractive colors" - if you print cyan, magenta and yellow inks on paper, they ought to absorb all the light shown on them. Your eye receives no reflected light from the paper, and perceives black