>>snip Thanks guys for the feedback - just confirmed my own misgivings about using glass carriers again. I will try them out but guess I am looking for the glassless carrier inserts for the 138S. The cardboard versions I made do not grip the film enough to keep it flat. >>snip Might try balsa or basswood, or spruce from your local model airplane hobby shop. They also have plywood from 1/64th inch to 1/4th inch.