When I make a screen using my Thermofax, I finish the edge with duct tape, and print the image on the outside of a folder. I now take it one step further and make an image on plastic to use as a designing tool; this is stored in the folder also. It's a great time saver to have it already done and wonderful for the designing process.
I buy the plastic at a chain sewing store. It's on a roll and sold by the yard. I think it's 4mm weight but not positive. It's a nice weight to work with.
I lay it over a piece of fabric or part of the quilt itself to see how it'll work.
This is one of my favorite designs as I love the movement; I haven't used it yet.
Previewing it over fabric
This next fabric is too busy for the intricate nature of the design.
This is a feather I found on a morning walk which made into a wonderful screen.
And here it is over a piece of fabric.