Many contemporary logos have complex gradients and color overlays in them, which create a bit of a challenge to reproduce on a t-shirt or poster. Screen printing is a stenciling process, that pushes ink through a piece of polyester onto the substrate below. In order to print multicolor graphics, a separate screen must be prepared for each color printed, as only one color of ink can go through the stencil at a time.
In order to create the illusion of gradients, we use a process called halftoning. Halftones allow gradients and tonal changes to be printed as a series of dots, which give the illusion of color change. These shirts for Kung Fu Rice Noodle are a great example of this process at work. A white underlay of ink was printed on a black shirt, and yellow halftone and a red halftone screens were printed on top to create the gradient look of yellow/orange/red.