Patent ID: 7846639

Claim:
A precursor printing form comprising a layer of a photopolymerizable composition sensitive to actinic radiation from a source of radiation having a range of wavelengths greater than 10 nm, wherein the photopolymerizable layer has a thickness range of 0.010 to 0.250 inch, further comprising at least one additional layer adjacent the layer of photopolymerizable composition, the additional layer selected from the group consisting of a support layer, a release layer, a second composition layer sensitive to the actinic radiation, an elastomeric layer capable of becoming sensitive to the actinic radiation, a wax layer, an adhesion modifying layer, a laser-radiation sensitive layer, a coversheet, and combinations thereof, wherein a photoluminescent tag comprising a metal complex of a lanthanide metal excluding optical brighteners is disposed in the at least one additional layer and is responsive to at least one wavelength from the source of radiation to generate emitted radiation at a wavelength that is different from the actinic radiation, the composition being sensitive to the at least one wavelength.