Abstract: A latent image development system comprising a substrate having a latent image thereon and an instrument for dispensing a color developing agent over the image. The image contains a carboxylic or organic sulfonic acid salt of zinc, mercury, copper, iron, cobalt, aluminum or titanium and a binder for the salt. The dispensing instrument contains diiphenylcarbazone or a ring substituted diphenyl carbazone derivative.Also disclosed are a crayon for use in developing a latent image, an ink for producing the latent image, a method for producing the crayon, and a system for use in printing and developing a latent image system.

Abstract: Preprinted duplicating masters for producing printed copies, with or without spirit duplicating fluids, comprising a foundation sheet reverse printed in a predetermined pattern with an imaging material which produces copies upon the application of pressure alone, although the spirit duplicating process can be used. The imaging material is applied as a synthetic polymeric resin disperion having an ink composition therein and is subsequently heated to gel but not fuse the resin so that the ink composition will be retained therein but will be releasable and transferable in a predetermined pattern to a substrate by at least the application of pressure alone. A protective cover sheet is placed over the printing to prevent inadvertent and accidental transfer of the ink composition.

Abstract: The spirit duplicating masters are pre-printed on a sheet having an oleophobic surface and utilizing, if desired, a non-bleed, non-smear ink composition. The result is a pre-printed master having no problems with bleed, smear or registry. Such pre-printed masters may be formed into booklets.

Abstract: A pre-printed spirit duplicating master containing visible imaged material and latent imaged material for use in preparing copies for self-instructional examination or work assignments. The latent images on the copy sheet are capable of being revealed with a pen containing a chemical developer and this can be done by the student in self-examination. The use of the pre-printed masters frees the teacher from the chore of preparing exams, or work assignments, making the masters, and from grading the papers.

Abstract: The spirit duplicating masters are pre-printed utilizing a non-bleed, non-smear ink composition. Typically the ink may contain cetyl alcohol, carnauba wax, a soft wax, fillers and a small amount of dye solubilizer and/or wetting agent. Such pre-printed masters may be formed into booklets without the necessity of interleaved protective layers or tissues.