Illustrator CS4 New Color Swatches Keep Shifting Values

Question

Hi.  I really need some help.  I created 8 major panel designs for my first-ever tee shirts.  For this project, I added up to 70+ colors to my existing standard CMYK swatch library, by naming them and marking them for global.  Just to be on the safe side, I also made up my own directory in a separate document by making squares with their names next to them.  I transferred these to each new document I created.  I did all of this in Illustrator 10.
I finally got to upgrade several months ago to the Design Suite CS4 -  Hooray!  No problem in converting my files.  I am having my tees printed in the direct-digital-to-fabric method.  My printer said that I could change all my CMYK colors to RGB for a more vibrant rendering.  And so I went in to each of my colors and manually changed them to RGB.  I also changed my document format to RGB.
Several weeks ago, my eye registered that my favorite red didn't seem as red any more.  And so it wasn't!  I checked my swatch, and it was way off my original settings.  So I changed them.  The change didn't keep.  It turns out that almost all of my colors were off their original CMYK settings!
So I started over again, by taking each color, and in most cases, making up a new color swatch with a slightly revised name.  I made sure the colors reflected accurately both the CMYK and the RGB percentages.  I DID NOT want to select as a spot color.  Therefore, I kept the "Process" format, but selected RGB.  I also deleted the old color swatch.
But the problem was still there -- within a span of several minutes, my "Red" changed both in the CMYK and RGB percentages,  I checked 15 other colors I had just created, and their percentages were off also.
Needless to say, it is very important to me that my colors hold their value.
I thank you in advance for considering my challenge.
Kelly Greenlee
[email protected]

Answer 1

Kelly,
And so I went in to each of my colors and manually changed them to RGB.  I also changed my document format to RGB.
Pick (almost) any colour in a document with CMYK Color Mode, copy into a document with RGB Color Mode, and see a change.
In other words: if you want to keep the colours, keep the colour mode; if you want to change the colour mode, recreate the colours, and expect some differences.
My printer said that I could change all my CMYK colors to RGB for a more vibrant rendering.
Maybe your printer needs a vibrant rendering, with a boot.
If the meaning was that the RGB colour gamut is larger, and therefore capable of more, and more vibrant, colours, which is true, that is what should have been said. It would imply creating new, fresh colours.