The simple fact is that there is no direct translation from CMYK to RGB because these different color models are built on a totally different basis in physics. RGB is an additive color model because you're dealing with points of light (glowing phosphor dots on a CRT or back-lit crystals on an LCD). CMYK is a subtractive color model for ink-on-paper reproduction. The color you see is a result of all the wavelengths that are not absorbed by the ink, which is why it's called subtractive; the ink subtracts out all undesired wavelengths from the (presumably) while light that illuminates the page.
The problem is that RGB can only simulate CMYK because the models are so fundamentally different, and there are dozens (if not hundreds) of different mathematical algorithms for how to translate values in one model to the other. The one thing you know when you work with CMYK color definitions is that if you make color separations and furnish the films (or files) to a print vendor, you'll get the same results regardless of what tool you used to generate the separations. But it's virtually guaranteed that the printed results will match *neither* tool's on-screen simulation of the color. Probably not even close. If you're trying to design a CMYK color that has a particular appearance, the only right way to do it is to work from printed samples and then simply live with whatever screen representation you get in a particular tool. Or if the color is only being used as a spot color you can use the Pantone color matching system (or an equivalent) where you pick a color from a set of swatches and refer to its reference number when you provide your job specifications to your print vendor. My opinions only; I don't speak for Intel. Fred Ridder (fred dot ridder at intel dot com) Intel Parsippany, NJ -----Original Message----- From: framers-bounces+fred.ridder=intel....@lists.frameusers.com [mailto:framers-bounces+fred.ridder=intel.com at lists.frameusers.com] On Behalf Of Gillian Flato Sent: Thursday, August 17, 2006 8:12 PM To: framers at frameusers.com Subject: Color definition problems Gurus, When I create a graphic in Adobe Illustrator and I enter the CMYK color definition of 100,0,76,15, it displays as dark green. When I enter those same CMYK settings in the Color definition area of Frame, it comes up as a Kelly green. They aren't even close. What is the problem? Why are they so different? How do I fix this? Thanks, Gillian Flato Technical Writer (Software) NANOmetrics, Inc. 1550 Buckeye Dr. Milpitas, CA. 95035 (408.435.9600 x 316 7 408.232.5911 * gflato at nanometrics.com <blocked::mailto:v at nanometrics.com>