Return Color Chart
There are three main visible components to a channel letter. The acrylic face, the edge return and the trim cap that holds the two together. The return of a channel letter is the side. It's what gives it depth and gives us a "channel" to put the lights into. The color can be the same as the acrylic face or it can be different. Black 3", 5" and 8" (with 5" being the standard for front lit channel letters.)
Channel letters are made of powder coated aluminum and colored to spec. Here are some popular colors but any color can be achieved.