Expert: Kevin Stohlmeyer - 8/25/2009

Question
hi, just done a 2 colour job.  the two colours were 100k and 100m. I mixed them up with the cmyk sliders. The job was in rgb but i used the cmyk sliders. when run out, 100% k turned into 63.53c, 67.17m, 63,67y and only 78.83k! completely ruined a two colour  job. how? why? i've been in the print trade for 30 years and always done stuff like this. quark doesn't do it - nor freehand. i'm a bit scared to use adobe stuff now it seems to have a mind of it's own. and even worse it doesn't tell you.

Answer
Hi Similar1,

The issue is that you created CMYK values in an RGB Color mode. When you convert RGB to CMYK, the RGB colors match the appearance of the color but do not automatically convert to what you expect it to. You should have created this in CMYK exclusively if the values were that important. This is a normal function of Illustrator and Photoshop as well. You can set these either when you create a new document or after under File>Document Color Mode.

Every application that converts RGB to CMYK including Quark and Freehand will change your expected CMYK values. The difference between Quark and Freehand is that they allow you to have both RGB and CMYK natively in one document, which Illustrator does not. If you were to create an RGB Magenta and then transfer it to CMYK, your values would mirror Illustrator.

Being from the print industry myself, I can tell you that it is a dangerous game using RGB in CMYK documents and vice versa. It may work for you now but with upgrades and newer applications, they do become more accurate with how they handle color and it may not work for you every time. Id stick with CMYK color modes if that is your intended outcome.

Kevin