Single sheet color proofing system

Claim 2

A presensitized color proofing sheet comprising a carrier sheet having a smooth release surface; a color coating of a diazo oxide and a pigmented resin compound in clinging engagement with but not adhesively bonded to said release surface of said carrier sheet; a binder layer comprising a mixture or reaction product of a resin and a diazo oxide bonded to the surface of said color coating; said binder layer being free of color pigment; and said color coating and said binder layer being solubilizable in a solvent developing medium upon exposure to actinic radiation but not solubilizable in the developing medium prior to exposure to actinic radiation; and a clear barrier layer firmly attached to said binder layer, said barrier layer being insoluble in said solvent development medium.

Claim 3

The presensitized sheet of claim 1 wherein said barrier layer is comprised of a heat activated adhesive.

Claim 4

The presensitized sheet of claim 2 wherein pressure-sensitive adhesive is applied to the previously applied heat activated adhesive.

Claim 5

The presensitized sheet of claim 2 wherein a release liner is attached to said barrier layer.

Claim 6

A method for obtaining a multicolored color proofing sheet image on one substrate comprising (a) bonding the barrier layer of a first presensitized sheet of claim 1 to a substrate; (b) removing said carrier sheet; (c) exposing said presensitized sheet through a color separation positive corresponding to the pigment of said color coating to actinic radiation whereby the exposed diazo oxide and resin mixture of said binder layer and said color coating is rendered soluble in an alkaline solvent developing medium to create a latent image; (d) developing said image with an alkaline solvent developing medium whereby exposed diazo oxide and resin mixture in said binder layer and associated color coating is removed and unexposed diazo oxide and resin in said binder layer and color coating remains; (e) bonding the barrier layer of an additional presensitized sheet as described in claim 1 having a different color pigment in said color coating to the developed first presensitized sheet; (f) repeating steps (b)-(d) with a subsequent separation positive being in register with said developed first presensitized sheet; and (g) repeating steps (e) and (b)-(d) in that order with additional presensitized sheets as described in claim 1, each of said presensitized sheets being of a different color, whereby there is provided said multi-colored proofing sheet on one substrate.