Abstract: A thermo-developable type diazo copying material is disclosed comprising a substrate and a photosensitive layer, formed thereon, consisting essentially of a diazo compound, a coupler and a color assistant, wherein said color assistant is at least a member selected from the group consisting of fatty acid amides having the general formula I:R.sup.1 CONH.sub.2(wherein, R.sup.1 is a saturated or unsaturated aliphatic hydrocarbon group having 5 to 24 carbon atoms), N-substituted fatty acid amides having the general formula II:R.sup.1 CONHR.sup.2(wherein, R.sup.1 is the same as defined above and R.sup.2 is an alkyl group having 1 to 5 carbon atoms, substituted or non-substituted phenyl group or substituted or non-substituted cyclohexyl group) and N-substituted fatty acid amides having the general formula III:R.sup.1 NHCOR.sup.2(wherein, R.sup.1 and R.sup.

Abstract: A two-component type diazo copying material according to this invention, which comprises a support and a photosensitive layer formed thereon, said layer consisting essentially of a diazo compound expressed by the following general formula I and a coupler mixture consisting of a compound expressed by the following formula II, a compound expressed by the following general formula III and a compound expressed by the following general formula IV, can form a genuine black-color image and is especially optimum for preparing a secondary original used in electrophotographic copying machines. General formula I ##STR1## (wherein R represents alkyl radical having 1 to 5 carbon atoms; R.sub.1 and R.sub.2 represent substituted or non-substituted alkyl radical, aralkyl radical or cycloalkyl radical, or R.sub.1 and R.sub.2 may form a heterocyclic ring together with the nitrogen atom to which they bond; and X represents anion.) ##STR2## (wherein X is of no account or represents O, S, SO or SO.sub.2.) ##STR3## [wherein R.sub.

Abstract: This invention provides yellow-developing couplers for use in diazo copying materials, which couplers are superior in light fastness and are expressed by the general formula: ##STR1## wherein X and Y represent hydrogen atom, halogen, or alkyl radical or alkoxy radical having 1 to 6 carbon atoms.

Abstract: A liquid developer for use in developing binary diazo copying materials which consists essentially of an alkali metal salt of an aminoacid and/or an alkaline earth metal salt of an aminoacid.

Abstract: A method of manufacturing a diazo copying material for use in preparing a secondary original, which comprises coating a water-dispersible precoating liquid comprising a porous powder, a binding agent and an anionic surface active agent having the following general formula on a transparent or translucent support and drying thereafter, and subsequently coating a photosensitive liquid consisting essentially of a photosensitive diazonium salt on the precoated surface of said support and drying thereafter.