Abstract: A transparent image sheet carrier for overhead-projection systems is described based upon a dark-tone colored field with image markings in bright-tone contrasting colors, including a sheet bearing a layer containing at least one acid-resistant dye for imparting the dark-tone color to the field; the dye may be discharged in the locale of the image markings by a discharge device with a simultaneous appearance in the image locale of the bright-tone contrasting color.
April 1, 1980
Date of Patent:
October 20, 1981
Norbert Mecke, Franz U. Schmitt, Karl-Heinz Schrader, Heinke Blutschkau
Abstract: Arrangement for applying written or drawn information onto image carriers for overhead projectors, characterized by an image carrier in film or plate form which comprises at least one colored compound, as well as a writing or drawing marker. The writing or drawing fluid of the marker contains at least one colorless compound which reacts with the colored compound to produce a color change.