Yes,

Tertiary colors are those colors generated on the printing press during production, This is where two colors like yellow and blue mix on the shirt or garment to create green. or red and blue to make purple. It is used mostly for the secondary colors from primary values But you can create browns and even use tints or tones to create differnt values of each color and tertiary color builds.

This is done printing the inks wet on wet. Some t-shirt printers using hand presses can do a ink blend inside the screen as well. Most will charge more for this as it is a labor intensive project.

Great t-shirt prints start with experienced t-shirt artist.