Window>>Colors

• You must convert all Illustrator colors to CMYK mode (see below illustration). That includes ALL fill colors, stroke colors and gradients.
  
• Do not leave colors in RGB mode. There is big possibility of a color shift when converting from RGB to CMYK.
  Do not trust your monitor.
  
• Make all objects/images heavy in BLACK color, a “RICH BLACK” (see below illustrations)
  
• Keep “rich” black consistent throughout your file (see below illustrations)

ALL FILES MUST BE IN CMYK:

All colors used in your files must be created or converted to CMYK mode. DO NOT save your files in RGB mode. There usually is a color shift when converting from RGB to CMYK. IF you are color critical, we highly recommend you order a "hard copy color proof" from 4OVER4.COM which you can choose during the ordering process. Our color proofs are SWOP calibrated and ONLY SWOP calibrated color proofs will accurately represent the color in your digital file. Do not trust the colors on your monitor unless your monitor has been calibrtaed to SWOP standards as well.

To Convert your file to CMYK, see below illustration

Filter >> Colors >> Convert to CMYK

MAKE OBJECTS HEAVY IN BLACK COLOR "RICH BLACK"

In order for your black borders, solids, headlines and parts of images to appear dark and saturated, aka "rich", you need to create a "new black" with the following CMYK values:

C: 60% :: M: 40% :: Y: 20% :: K: 100%

Illustration above depicts the difference in saturation between 1 color black and 4 color black. Printing only a 1 color black will cause your images to appear washed out.

KEEP "RICH" BLACK CONSISTENT

Please make sure to keep "rich" black consistent throughout your file. Make sure that logos or images with a black background have the same values as the black area it is placed over. In the illustration, the "4OVER4.COM" logo is in "rich" black but has been placed over a 1-color washed out black box.