In commercial 4-color printing, all final jobs are cut in stacks. The accuracy of cutting in stacks is never perfect. Sometimes, the pressure on the stack from the cutting blade will cause a slight shift on the paper, losing the precision of the intended cut. This is why bleed is necessary to compensate for the shifting.

If bleed is not provided on a document, the final result of a trimmed job may possibly result in a slight white border around the edge. The example below will illustrate why bleed is important.

CMYK is also called 4-color Process. Colors in CMYK images are composed of varying amounts of Cyan, Magenta, Yellow and Black. This is the way a printing press prints color, so it is vital that your image be in this color mode. For 1-color Process it needs to be grayscale or bitmap (which only use Black).

RGB is an abbreviation for Red, Green, and Blue. This is a color system commonly used for monitors, digital cameras, televisions, etc. This color system works well for DIGITAL items but not for printing ink on paper. You MUST convert your files from RGB to CMYK prior to uploading your files. You will notice that some colors (especially fluorescents), will convert to a much darker color. It is important you handle the conversion on your end so have a realistic idea of what can print, and choose your colors accordingly. Even better is to begin your new document in CMYK to avoid having to convert it later.