Abstract: Written, typed, penciled, inked, xerographic and other markings on foils, opaque and transparent papers can be erased easily by mechanical means by utilizing an interlayer of alkylketene dimer with hydrophilic colloids and pigments. The provisions of such an interlayer is useful for drafting materials, xerographic and diazotype copies.

Abstract: Erasable diazotype second originals on a translucent base have become very popular because they permit correcting, deletions and additions of new information to drawings without the need to redo an entire drawing. A new barrier film composition that acts simultaneously as matrix for the diazotype coating components and controls the ease of mechanical erasure is disclosed. The second originals exhibit almost film like reprographic continuity.

Abstract: Diazotypes with new yellow coupler with an active methylene group are disclosed; the couplers do not migrate and excel by their relatively reduced coupling speed for greatly improved shelf life of diazotypes. In preferred embodiments the improved new diazotypes contain acetoacetoxyethyl methacrylate or acrylate as yellow coupler.

Abstract: A transparentized paper with a caliper of between 0.001 and 0.015 inch and the process for its preparation is disclosed. A paper web is treated with a liquid mixture of polyesters, acid monoesters of polyols and dicarboxylic acids in non aqueous polaric solvents having admixed therein methylol derivatives of polyamino compounds, with or without a catalyst. The impregnated paper is cured by an in-situ cross-linking reaction immobilizing the impregnated material. A transparentized paper results which is resistant to water, most organic solvents and heat and is useful as tracing material as well as a translucent base for sensitizing with reprographic coatings. The transparentized paper is not resistant to alkali and can be repulped in alkaline medium for recycling. The transparentized paper also exhibits antistatic properties.

Abstract: Zinc salts of sulfonic acids are described as stabilizers for diazotype materials.

Abstract: Fibrous sheets are transparentized by coating them with monomers of the formula: ##STR1## wherein R is hydrogen or lower alkyl and n is an integer of 0 to 6; and polymerizing the monomers.

Abstract: Disclosure is made of a class of diazonium salts characterized in part by their improved thermal stability and non-flammability. The salts are useful in diazotypy.

Abstract: One component diazotype material is imagewise exposed and developed odorless and curlfree with 0.6-4.5 g/m.sup.2 per square meter of a substantially water free liquid developer in a pressure development or transfer roller apparatus.

Abstract: A transparent, non-stratified, three dimensional resin reinforced fibrous sheet and the process for its preparation is disclosed. A fibrous sheet is impregnated or coated with one or more tri or higher functional monomers that can be polymerized in-situ to form three dimensional polymer resins, in close contact with the fibrous material of the sheet. A transparentized fibrous sheet results which is resistant to water and alcohols, highly and evenly translucent and useful as tracing media vellum as well as a translucent base for sensitizing with reprographic coatings.

Abstract: A diazotype material, which comprises a supported light-sensitive layer comprising a light-sensitive, water-insoluble diazoimino compound of the formula: ##STR1## wherein R is an aryl group and R.sub.1 and R.sub.2 are organic radicals, which may be the same or different, or R.sub.1 and R.sub.2 together with the nitrogen atom to which they are attached form a heterocyclic group, an azo coupler, and an alkaline material, said diazoimino compound, when exposed to ultraviolet light, being reactive with said azo coupler to form a visible dye product only at a pH greater than 7. The diazotype material can be used for diazotype reproduction processes resulting in negative or direct positive images.