4-Color Process Or CMYK Printing: This is probably the most complex of the printing processes and is recommended for automatic presses only. Although it may be done on a manual printing press, optimum and consistent results will be achieved only on a fully automatic tee shirt press. Here we take a full color photograph or image and break it down into its four constituent colors; cyan, magenta, yellow and black.
CMYK doesn’t always achieve every color in the spectrum perfectly on T-shirts, but it does get the idea
across in a very effective way. The only down side i see to process printing is it only works on light colored shirt ( best of white )
Simulated Process Printing: This is a combination of spot color printing and the 4 color process printing concept. This is done by printing spot colors with halftone dots to create the “ Simulated” colors from the original image. This allows us to achieve a broader range of colors in the print while actually using much less.
This was brought to the market in the 80’s as a great way to do photo realistic images on dark shirts. For instance a 50% yellow dot over blue will create green without having to use a whole new screen. This can be done on light garments and will require a white underbase on dark garments.