CYMK colors won't match

Question

I am currently studying graphic design. I am using the Against the Clock portfolio builder for Adobe Illustrator CS6 to learn the program. I have had no problems until recently.

The book is asking me to set my CYMK color value to C15-M25-Y45-K0. The resulting color, as shown in the book, is a golden yellow sort of color. However, when I put the exact same color value in my Illustrator program, I instead get a very faded brown. To get a color similar to the one shown in the book I have to set the value to C5-M50-Y100-0, which is drastically different from the value given to me.

I have provided a link so you can see what the two values look like. On the left is the color with the value provided in the book, on the right is close to what the color should look like.

^{Click image for full resolution}

(Never mind the second open file. I opened it after I saw the color not coming right, since I new it had object with a similar color to what I needed.)

I have followed the book to a t, and I have gone over all the color setting to make sure that they are correct and, as far as I can tell, it is correct. I have also printed out the images, to see if it was perhaps simply my screen messing up the colors, but the color is the same when printed.

Answer 1

CMYK, as you likely know, refers to printed colors. Your screen, however, uses RGB color space. RGB and CMYK will never match exactly, as they are different color spaces. Your screen can merely approximate what you'd see on paper. In addition to that, every monitor has different settings...brightness, contrast, etc, etc, so even getting two monitors to match is a bit of a crapshoot.

Finally, you're looking at a CMYK approximation on screen, that was then screen shot, then put back into CMYK to be printed in the book. :)

Long story short, this is just how it is. Don't expect what you see in the book to match your particular screen.

Answer 2

As DA01 mentioned, you can only get so close in reconciling CMYK and RGB colors. But if you feel that the colors are truly out of whack, it could be a simple mistake by the publisher. The only way to tell is to use a printer's loupe (or magnifying glass, microscope, etc.) and look at the printed color.

Answer 3

Be aware, with Illustrator, if you open a new document with the Document Color Profile set to RGB all library items (Swatches, Brushes, Symbols, etc.) are defined using RGB colors. If you then merely use File > Document Color Profile to change the document to a CMYK file, all those libraries remain defined as RGB. They don't change or update to match a CMYK document color profile.

This can often cause unexpected color definitions for CMYK colors. It's important to start a document as CMYK if you want to end with a CMYK document.

Selecting all, copying, created a new (CMYK) document, and pasting may yield more expected results.