| abstract |
A phototranschromic ink suitable for use in a printing machine, including a water soluble, inert, nonionic polymeric resin carrier base having film forming properties, a photo acid or photo base progenitor which releases or takes up protons upon exposure to light, a pH sensitive dye which changes color in response to a change in proton levels, a water compatible non-ionic wetting agent, a water compatible non-ionic thickening agent, a neutral water soluble flow aid; wherein said ink changes color upon exposure to ultraviolet radiation and is of suitable consistency for use in a printing machine. |