In the present invention, one produces a negative-acting color proofing element comprising, sequentially: a strippable cover sheet which is transparent to actinic radiation; a crosslinked layer containing a polymer having phenolic groups; a color layer, containing a colorant, a polymeric binder, a polymerizable monomer and, optionally, a photoinitiator; a photoadhering layer, containing a linear photosensitive polymer containing ethylenically unsaturated, free-radical polymerizable groups and having a weight average molecular weight greater than 3,000, a polymerizable monomer, and, optionally, a free radical photoinitiator, a thermoplastic adhesive layer; and a receiver sheet, at least one of the color layer and the photoadhering layer containing the photoinitiator, which comprises at least one of (I) a chromophore-substituted bis-trichloromethyl-s-triazine, (II) a combination of an acyl or diacyl phosphine oxide and a fluorescent optical brightener, or (III) a combination of a hexaaryl biimidazole compound, a chain-transfer agent and a fluorescent optical brightener.
NEGATIVE WORKING, PEEL DEVELOPABLE, SINGLE SHEET COLOR PROOFING SYSTEM WITH IMPROVED BACKGROUND COLOR