[Chimera-users] RGB->CMYK color conversion

Dear Chimera users, I am writing to see if there are suggested methods for ensuring good color conversion of rendered Chimera images from RGB to CMYK in Photoshop (or other image editing programs). When printing to a Tektronix Phaser 740 color laser, I am getting poor correlation between screen colorings and the printed ones. I have heard that the CMYK color space is basically a subset of the RGB color space. If this is actually the case, is there a recommended way to pick RGB colors that are relatively "safe" for conversion to a CMYK color space? Thanks, Jim Puckett