High quality vellum like paper designed for laser printers and copiers. Screen Printers use this laser printer output as a positive for burning screens. Why? Because Casey's Translucency is less expensive than film and saves the cost of a camera. Casey's is also more durable and more stable than other vellums, meaning it won't shrink and wreck your separations. Finally, Casey's is designed specifically for use with laser printers and copiers and won't jam or damage your printer like cheap vellum.