Kreene is one of the must-have items for making plates. If you are using a traditional split-back printing frame or glass-topped vacuum exposure unit, this indispensible piece of frosted plastic will ensure that there are no weird Newton's rings or other light-altering phenomenon occuring between the surface of the glass and your positive transparency. Place it between the positive and the glass on the printing frame or exposure unit vacuum frame. Works like a charm. Or even better, replace the glass topped vacuum frame with a steel frame holding a Kreene blanket instead of glass!
The Kreene we sell is a commercial version that is used in the flexographic printing business, and is a little more expensive than the Kreene offered elsewhere. It has two lightly frosted surfaces and is impossible to accidentally place upside down.
We sell it cut slightly larger than the standard European plate sizes that we sell. With reasonable care, one piece will last for some time.