cmyk formulas are changing unexpectedly 1

[nicksims]

Using WinXp and CS2.

This has been happening in a few different files. I've got a cmyk formula that I've entered (for a graphic drawn in Illy- not placed or copied from another program).

In the latest case, the formula was something like 70/100/100/20. I print, then I go back to the file and check the colors. The cmyk is now 69/98/100/24. Subtle, but I am trying to match a color. The numbers here are approximate, but they are simply different then what I originally entered. I don't think it is related to the printer either since it was also happening prior to printing- ie. I would enter the formula, work on another part of the file, go back and check and the numbers are just slightly different.

Would this fall under the issue of aiprefs file glitches and it is time to delete it?

Thank you.
Nick

 

[apepp]

...sounds like your document colour space is rgb perhaps?

...change it to cmyk document space, fix your values, save the file and reopen it...

andrew

 

[apepp]

...in cs2 this is found in file > document color mode, make sure you are in cmyk not rgb...

andrew

 

[nicksims]

Yep. Perfect.

Not sure how, but I must have changed that some time ago. I don't normally use rgb, so who knows what I was thinking?

Thank you very much.

Nick

 

[apepp]

...easily done though, the clue can be found in your documents window title bar, in brackets you will either see cmyk or rgb next to the name of your document, also your swatch colours will have an rgb icon to the right of the name...

...i would advise you to check your existing artwork carefully, as you have discovered, a shift from rgb to cmyk will change the colours, this conversion is controlled by the use of the color settings profiles when images are involved...

...i would advise all your adobe products be using an identical profile set up. RGB images placed in a CMYK document and embedded will be converted to CMYK, linked CMYK images in an RGB document will remain CMYK. This depends on how your color management options are setup.

An RGB image linked in a CMYK document will remain RGB, an RGB image embedded in an CMYK document will be converted to CMYK. This depends on how your color management options are setup.

This conversion is controlled by the color settings profiles. I recently experienced a page spread being resupplied from a client, output only the half that had changed keeping an older version of the side that had not changed, (the image covered two pages), this ended up on press with a difference between the colours, nightmare!

Turns out the designer had an RGB image linked, saved to CMYK eps (image embedded before creation), all text to outlines. Second time around a different profile had been used shifting the colours of it. Spreads therefore didn't match, text correctionc were fine though.

andrew