Common Color Separation Issues | Printing

One of the most common mistakes that causes a great deal of headaches are color separation issues. Many designers and printers run into images that haven't been converted from RGB to CMYK. Computer monitors emit RGB colors to create all of the images that you see on a monitor, while printing uses CMYK (cyan, magenta, yellow, and black) which act as a filter for light that is absorbed or reflected creating all of the colors that we see.

Photographs and transparencies usually contain a broader color gamut than can be printed. Often times designers will send a photograph to prepress to have the image scanned and color corrected. Prepress then returns a low-resolution file for page layout, and the high- resolution file is incorporated into the final page and a proof is generated. The designer may discover subtle color changes to the image which can be attributed to the image containing more colors gamut and density than process inks can print.

If you are working with images that you suspect may cause problems ask your printer’s prepress department to return a proof using the high-resolution image so you can see if there is going to be a problem. If you have any doubts get a proof. It's easier and less expensive to make changes early in the production cycle. If you are working with studio still photography, select photographers who know how to work with prepress services and who use measured photography to minimize such problems.

Remember that scanned images must be converted from RGB to CMYK before they can be used to create proofs or added to the page layout. For best results use a color management system with an RGB-to-CMYK conversion.