CMYK REFERS TO THE FOUR INKS USED IN STANDARD COLOR PRINTING: CYAN, MAGENTA, YELLOW, AND KEY (BLACK).
All of our standard printed products are produced using CMYK because standard printed products are gang printed. This means that a job is stepped up or nested, on the same sheet of paper, with several other jobs that are the same size and have the same quantity. This is done to reduce and share the setup costs of printing. As a result they have to be printed using the same inks (CMYK).
The use of spot colours (also known as PMS, Pantone or special colour) costs more as the set up cost is for that single job.
Small quantities are best digitally printed which exclusively uses CMYK.
It is also cheaper to print CMYK than to print 1 or 2 spot colours, as the printing press is set up for CMYK. Spot colours require a special set up which you will have to pay for entirely.