THE NEWLY DEVELOPED TECHNIQUE INVOLVES THE USE OF 4-DIMETHYLAMINOCINNAMALDEHYDE (DMAC) WHICH REACTS IN AN ORGANIC SOLVENT WITH UREA UNDER ACIDIC CONDITIONS TO GIVE A MAGENTA-COLORED STABLE PRODUCT. COLOR DEVELOPMENT IS COMPLETE WITHIN A FEW MINUTES AT ROOM TEMPERATURE AND THE COLOR CONTRAST BETWEEN THE FINGERPRINT RIDGES AND THE RIDGE INTERSPACES IS SUCH THAT EXCELLENT PHOTOGRAPHIC RECORDING ON ORTHOCROMATIC FILM WITHOUT THE AID OF FILTERS IS POSSIBLE. THE REAGENT IS ESSENTIALLY SPECIFIC FOR UREA-THE REACTION WITH AMINO-ACIDS AND AMMONIA BEING NEGLIGIBLE BY CONTRAST. ITS OVERALL SENSITIVITY IS EQUAL TO THAT OF THE MOST SENSITIVE NINHYDRIN FORMULATION FOR AMINO-ACIDS. (AUTHOR ABSTRACT MODIFIED)