Term Tuesday: Process Colors

Jacquard Professional Screen Inks are best known for their ability to be screened onto non-porous, as well as porous surfaces, and for their durable (un-scuffable!), semi-glossy finish. They also are known for their long open time (meaning you can use them for long periods of time without having them dry in your screen) and for air curing (meaning you don’t need to heat set if you can give the ink 72 hours to cure before washing). They are available in standard (semi-opaque colors), and opaque colors (including metallics). They are also available in Process Colors. (pictured above). 

From Jacquard’s online glossary: "Process color is

a system of using four standard, semi-transparent inks to create a wide spectrum of colors by mixing them on a press or substrate."

There are different ways of approaching color mixing. In print applications, process colors are distinguished from “spot” colors. Spot colors are colors that are mixed prior to printing. This is perhaps the more intuitive method of printing: each color is pre-mixed and gets its own plate or screen. Dark colors are printed on top of lighter colors. For images with many colors, however, using spot colors can get expensive and laborsome.

Process printing refers to the process of building colors directly on the substrate during the printing process. This is a much more cost-effective method of building color: you only need four colors of ink, and you won’t have any leftover, wasted ink after your print run. A maximum of four screens/plates are needed for process printing, which makes everything easier, less time consuming, and less expensive. 

As an artist or designer, you are very likely to be familiar with this term. Others may recognize process colors from the abbreviation, CMYK, which stands for Cyan, Magenta, Yellow, and Black (or Key). The colors are printed in this order (light hues on top of dark hues, black last). Process colors are semi-transparent: when one color is printed on top of another, a secondary color is produced. Printing yellow on top of cyan, for instance, produces the color green. Separating an image into the four process colors and burning halftone screens for each allows printers to simulate practically every color in the spectrum. This is how photographs are typically reproduced for screening. Even if you are not printing photographic images, or if you are not interesting in printing half tones, using process colors can be an extremely cool way to print. 

This photo illustrates the use of halftones (via)

The idea is really quite simply: overlapping semi-transparent inks produces additional colors, right on the printed surface. This opens a number of creative possibilities for a screen printer. Think about overprinting different geometric patterns, for instance: secondary patterns will emerge in their own secondary colors! You can even use an extender to make any of your spot colors semi-transparent. This will allow you to create a multitude of colors on your substrate, just by overlapping different inks. 

Print by Asher Katz

This is our second Term Tuesday. For even more textile terms, be sure to check out our glossary.