I have a couple of Xerox printers that I have made color profiles for and from trial and error it seems that the profiles only work if I UNCHECK preserve CMYK numbers. Is this correct and should I be leaving this unchecked? I am very ignorant when it comes to color profiles, but I am trying to learn.
The only downside to leaving this unchecked seems to be that black type and barcodes seem to be a buildup of color rather than a pure black.
That's correct. The numbers need to change to preserve the appearance when you convert to a new profile, but he downside is that your black also needs to change to a 4-color black to preserve its appearance as well.
If the final destination is the xerox, why not assign the xerox profile as the document working space?