On some of my InDesign CS3 documents, the preset color swatches ALL spontaneously change (so that a 100C, 100Y swatch becomes a 95C, 3M, 89Y swatch). This happens after one of my colleages works on the document, but he says he's not doing anything. Why does this happen and how do I prevent it?
The document's color management CMYK policy was probably set to Convert to Working space when it was created. In that case the swatch numbers will change if the Color Setting's CMYK Working Space doesn't match the document's profile when it is opened.
To change a document's policy, close it, set the Color Settings Policy to the one you want, and check Ask When Opening. Reopen the document you you'll get a dialog that lets you change the policy: