How To Do Iris Folding

From Sherri Osborn, former About.com Guide

Now we need to fold each strip of paper/fabric in half, lengthwise. The folded edge will show inside your design window. This gives it a crisper, more distinct edge. If you are using fabric strips, use an iron to get a crisp seam along the folded edge.

The only problem with folding your strips in half is that it makes your finished project thick. For a thinner finished project, cut your strips so they are approximately 1" x 6" and then do not fold them in half. You can experiment with both ways and use whichever one suits your need on a project by project basis.