Results revealed that the experimental formulations developed large number of darkly colored fingerprints in an analogous manner to the CFC113-based formulations currently used by police agencies in the United Kingdom. Results demonstrated that the use of both HFC4310mee and HFE7100 as solvents for ninhydrin have significant advantages over formulations based on hydrocarbons in terms of both efficiency and safety. Another advantage is that these solvents are relatively non-polar and therefore do not cause diffusion of handwriting inks. Large trials using operational materials will be conducted before either of these formulations is introduced into the laboratories of the police service. Figure and 5 references (Author abstract modified)