Color Dies in CMYK

I do some stuff for a independent hot rod car magazine. I sent him some shots of a really brilliant blue 56 Mercury. He says that some colors like blue, green, and purple die when he converts to cmyk for the printer. Is there anything either one of us can do to help or is just something that happens no matter what?

Thanks for any help and advice.

How is it being printed? Offset lithography?

Those three colors generally do flatten in CMYK printing. CMYK printing has a smaller color gamut than RGB (although CMYK can actually reproduce yellows that are not visible on a color monitor). You can get an idea of what each color space can reproduce here. One way around the limitations of CMYK is the use of custom inks in the printing that are outside the normal CMYK range. This is also why desktop inkjet printers have additional cartridges, usually a combination of red, blue, and/or green, as they expand the range of reproducible colors.

I don't really know I'm guessing offset. Thanks I will check that link out when I get home. I dug out my "Real World Photoshop" book to see if it helps as well.

Have a read in the link from my sig about softproofing: You might want to softproof and 'correct' some of the color loss using adjustment layers...