Simulated Process is similar to the 4CP, but it is designed to work well on darker garments. Unlike the translucent inks used in 4CP, regular high opacity plastisol covers the dark garments better and produces more vibrant images. It is also not restricted to four specific colors (CMYK) so some of the shades not available in 4CP (orange and brighter shades of green for example) can be reproduced by using Simulated Process.
Most of the garment printing seen today is actually done using the Simulated Process printing. It provides a wider color gamut and more vivid colors. As the separations are a highly complex process, they require years of training. We outsource all our separations to Dot-Tone-Designs in Orlando FL. The work is done manually and takes hours to complete (some of our award winners took 8-10 hours to separate!). Skilled labor at the world class level is expensive so the simpler designs start at $40 and can go as high as $500 for the highest grade, high color count separations.
Here is a good example of the color build in an eight color design: