This may not be helpful, but . . .
I've been fingerprinted a couple of times for background check purposes, and each time, the prints were deemed unacceptable, and had to be redone. And in comparing notes with others who've needed prints for background checks, this does NOT seem to be at all unusual.
If a certified fingerprint tech using a standard fingerprint kit with a co-operative subject has difficulty getting prints deemed acceptable enough to establish my identity by law enforcement, put me firmly in the "skeptics" column when it comes to lifting latent prints of sufficient quality to be acceptable for evidentiary/forensic puposes in regard to a crime.
I know this flies in the face of a great deal of police science . . . but in cases like this I put a lot more weight on personal experience than I do on what's "accepted" knowledge.
