UNDERSTANDING RGB AND CMYK
What is the difference and how does this affect you?
Well, scanners and digital cameras create images using combinations of just three colors: Red, Green and Blue (called “RGB”). These are the primary colors of light, which computers use to display images on your screen. Printing presses print full color pictures using a different set of colors, the primary colors of pigment: Cyan (blue), Magenta (red), Yellow and Black (called “CMYK”). This is “4-color process” or “full-color” printing that comprises the majority of magazines and marketing materials you see every day. At some stage your RGB file must be translated to CMYK in order to print it on a printing press.
It’s Best If You do the RGB-to-CMYK Conversion of Your Images. You will have more control over the appearance of your printed document if you convert all of the images from RGB to CMYK before sending them to your printer, who normally will do a standard-value conversion to CMYK, from your RGB file, which may not be perfectly to your liking. It is worthwhile to take time to prepare your files correctly, as your printer won’t be responsible for sub-par results when images are supplied in RGB. – Although monitors always use RGB to display colors, the colors you see on your monitor will more closely match the final printed document if you view them in the CMYK color space.
Be aware that it is possible to see colors in RGB that you can’t make with CMYK. They are said to be “out of gamut”. What happens is that the RGB-to-CMYK translator just gets as close as possible to the appearance of the original and that’s as good as it gets.. So it’s best to select any colors you use for fonts or other design elements in your layout using CMYK .
Here are some examples of how various RGB colors convert to CMYK:
You probably won’t notice this kind of color change in a color photograph. It is more likely to happen if you pick a rich, vibrant color for a background or some other element of your layout. It probably won’t look bad, it just won’t look exactly the same.