Dihydroxytetraphenylporphyrinatotin(IV), (TPP)Sn(OH)2, has been shown to react with latent fingerprints on paper. Comparisons have been undertaken against Physical Developer on prints that have been exposed to water, and against ninhydrin and DFO for prints on thermal facsimile paper. Results show that (TPP)Sn(OH)2 is not only compatible with Physical Developer but is also simpler to use and could be the reagent of choice for developing fingerprints on thermal papers. Porphyrins and phthalocyanines (a closely related class of compound) should be further investigated for their potential as fingerprint reagents. Their large range of different colors, reactivities and solubility characteristics offers many possibilities for developing novel, effective fingerprint reagents. Figures, tables, references