Preparing a file for Screen Printing

I'd be interested in knowing more about how to prep a file for screen printing. Screen printing is a very old technology (around 960–1279 AD in China and ironically patented in England by Samuel Simon in 1907) and credit is often given to Andy Warhol for popularizing the method with his works. But it is still particularly useful today as a way to print onto non-flat or unusual surfaces such as billboards, bottles, electronics, snowboards, balloons etc.

Because the process involves pushing ink through a mesh screen, the designs need to be carefully thought out in terms of layers. Not just the shapes of each colour but the order in which they are placed and any overlap areas which could result in an undesired colour change. This tutorial goes through the steps required to prepare a simple graphic for screen printing and really helps to start framing your mind to think about the layering process.