A diazotype copying material having a light-sensitive coating containing a diazonium salt selected from the group consisting of 2,5-disubstituted derivatives of 4-dibenzylamino-benzene diazonium salt exhibits a very high sensitivity to light.

On an apparatus for developing latent images of diazotype prints with a developer liquid containing an organic amine or amines as the developing agent, the tendency of the diazotype paper to curl and wind round the applicator roller is effectively precluded by the addition of a very small amount of a fluorocarbon non-ionic surface active agent. The amount of the agent is preferably in the range from 0.01 to 1% of the total weight of the developer composition.

A developer apparatus is provided for developing exposed diazotype copy sheets comprising an applicator roller, means for supplying liquid developer to the applicator roller, a metering blade for wiping excessive liquid from the applicator roller and a pressure blade for pressing a copy sheet against the surface of the applicator roller to transfer liquid from the applicator roller to the copy sheet to develop an image thereon. The metering and pressure blades are arranged for sliding movement b...

There is disclosed a method of producing diazotype photoprinting material in which a base paper is withdrawn from a supply roll and transported through a precoating station in which a solution containing a silicon filler is applied to one side of the base paper; the paper is then transported from the precoating station past a plurality of heaters to a sensitizing station in which a solution containing a diazotype sensitizing compound is applied to one side of the base paper; the base paper is th...

A liquid-carrying roller useful for applying controlled amounts of a diazo-developing liquid which is released in response to removal of the liquid from the surface of the roller. The roller is made of a porous solid resin such as polyethylene. The pores have an average diameter from 10 to 75 microns and contain an organic amine having a boiling point in the range from 105.degree. to 250.degree. and a pK value less than 4.70.

There is disclosed a diazotype copier for deodorizing developed diazocopy material. The copier includes a light source for exposing the diazotype copy material and a developing chamber for developing the exposed copy material. After exiting the developing chamber, the developed material passes under a heating chamber which includes a heating element and means for providing a flow of air into the chamber, around the heating element, and across the developed copy material. The heating air releases...

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.

A reserve supply of diazotype developing liquid from which liquid is supplied to semi-dry diazotype developing apparatus is maintained at both a substantially constant level and the required concentration of azo coupling component by introducing solvent for the liquid to restore the liquid level upon a decrease of the supply volume, sensing the specific gravity of the supply liquid by a hydrometer, and counteracting the decrease of concentration resulting from solvent addition by introducing a l...

An apparatus for producing a gaseous developer medium for a diazotype material from a developer solution, which apparatus comprises a vessel provided with a heater and an outlet for residual liquid, for generating a stream of vapor from a liquid, A conduit in which a stream of developer solution flowing in one general direction can come into contact with a stream of vapor flowing in the other general direction, which conduit communicates at one end with the vessel and is provided at, or in the v...

The invention concerns a heat, steam or water developing diazotype material, containing a photosensitive diazonium salt stabilized with a non-diffusing acid and also one or several developing coats--which could contain the coupling agent--located on the front or back side of the used base material, products avoiding the interpenetration of the active agents, preventing the washing of one coat through the another during coating process, slowing down the absorption of ambient humidity at normal te...