This forest graphic was converted to RGB in Illustrator
If you’ve been doing much graphic art creation, it may seem counter-intuitive to design in the RGB color space for something that will be printed. However, that’s what we ask you to do, and we’ll show you why here.
We learned when we got into direct-to-garment t-shirt printing that the print driver on our garment printer converts RGB files into CMYK files. It does so in a way that is optimized for garment printing. While this is a good thing, it sometimes confuses people who think of RGB as the color space for TVs and computer screens.
When you design for t-shirt printing, check that any art that you import into your t-shirt layout is also RGB. The photo below shows what happened when I forgot to check. Turns out it was CMYK and it dramatically shifted the colors when printed on a t-shirt. The greens shifted to black and the light blues darkened.
When left as a CMYK file, it printed dark turning some colors like greens into black
Fortunately, the fix for this problem is easy. First make sure that you have defined your document as an RGB file. In Illustrator this would be File>Document Color Mode>RGB color. Then select any art that you have imported and use the Edit>Edit Colors>Convert to RGB command.
If you have imported graphics that were once CMYK, as a safeguard you may want to re-color your art using swatches you build from scratch as RGB swatches. I frequently notice that art comes to us defined as an RGB document, but when I check the colors used, they show up as CMYK swatches. I check this by clicking on a color in the imported art and then generating a new swatch from it. If the color formula in the new swatch comes up as CMYK, then I know that the colors in that graphic need to either be substituted with new RGB colors or converted to RGB. Another way to tell is to open up the clipart file by itself in Illustrator and check the document color setting. If it says CMYK, then all the colors need converting to RGB.
