We start giving short definitions CMYK and RGB Colors first. CMYK is subtractive color used in printing, while RGB is additive color mostly used in display graphics on screen or web.
The name of the CMYK color mode stands for Cyan (a pale blue), Magenta (a hot pink), Yellow, and Key (or black).
The name of the RGB color mode stands for Red, Green, and Blue.
Some RGB colors that you can see on your monitor (such as bright vibrant colors) cannot be created with standard CMYK inks. These unachievable RGB colors are said to be "out of the CMYK color gamut." When selecting such colors for your print project, Lotus recommends start design in CMYK color to avoid potential RGB conversion problems.
Before to print on a four-color press, all RGB files must be converted into CMYK color. in such stuations, print houses does not take the responsibility of COLOR SHIFT that occurs in conversions from RGB to CMYK color modes.