Mike,Originally Posted by mikewhi
This may be your lucky day. I have a 50-sheet box of 5X7" Kodak Pan Masking Film, #4570, that was specially made for your application. It is long outdated but has been stored in a freezer from the time I purchased it, as I store all of my film. I opened the box some years ago and used a few sheets of the film but I am fairly certain that there are around forty sheets left in the box.
If interested the box is yours for $20 plus shipping.