laser-lovers@uw-beaver (04/09/85)
From: Brian Reid <reid@Glacier> As I watch the replies come back to Rick's note about transparencies I thought it would be worth mentioning the results of my explorations with transparencies in laser printers. There seem to be 3 kinds of material that overhead slides are made of: acetate, mylar, and polyester. The acetate slides are thick and fairly rigid and quite transparent. The mylar slides are thin and fairly flexible and very slightly milky. Polyester slides are thin but rigid. Acetate slides melt in laser printers or copiers. Acetate also takes fingerprints very easily, and is very susceptible to moisture. The reason that people use acetate at all is that it can be made to very high optical standards--very clear and very smooth. Mylar doesn't melt in laser printers, but it can be damaged by fingerprints and water. You can buy a special kind of mylar film that is treated with some form of silicone so that it is slippery enough to work in the paper-feed tray of laser printers or copiers that do not have single-sheet-feed capability (ask for Xerox brand copier transparencies at your office supply store). Polyester neither melts nor shows fingerprints, but it is quite difficult to write on polyester with erasable pens. I have never succeeded in getting polyester to feed from the paper tray; it is necessary to single-sheet-feed it. I use Stabilo polyester slides for everything--both for writing with pens and for printing in laser printers. It's great. Brian
peters@cubsvax.UUCP (Peter S. Shenkin) (04/11/85)
Mylar is somebody's (I forget whose) trade name for polyester film. Like other polyester film, it is available in a range of finishes and thicknesses. What keeps you from writing on these films is the slippery silicone coating added to allow feeding from paper trays. To write on the film, once your transparency has been made, swab the surface with a tissue moistened with rubbing alcohol (use vodka if you prefer). Then you should be able to write with a normal transparency marker. (Aren't you glad there's a chemist on the net?) Peter S. Shenkin, Biology, Columbia Univ., cubsvax!peters