Color separating for T-shirts

I hand separate and trap Illustrator artwork to produce film positives for silkscreening binders every day.

It's really nearly impossible to assist you with your project without seeing the illustration in question. I'd need to see how the colors overlap, as well as the colors used to determine what order the inks will go down so that we can then figure out what needs to trap to what.

For the record - jdanek is super correct - contacting the silkscreener would be the first step in determining how they want the file to be set up (and to determine if you even need to be worrying about this at all).

And, I can't resist mentioning that a very complex illustration built in six colors might not be a great candidate for silkscreening.

Pathfinder Trap will prove useful once everything's on its own color layer, but the main issue is getting all the white on the white layer (etc) and subtracting from those shapes any shape that overlaps it. I know it sounds like basic Pathfinder stuff, but again, it's a highly complex design with dozens of layers. Your head would explode if you tried using Pathfinder one shape at a time. The Shape Builder method is working out okay, but I still am having to work through the design one component at a time, or else it takes too long to process between passes.

Barbara, please. Even with two simple overlapping shapes, that method would instantly fail.