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Latent Print Examination » Questions from FP Experts for FP Experts... Processing, Testimony, and Technical Matters » Latent Comparisons from Photographic Negative « Previous Next »

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Donna
Posted on Friday, September 05, 2003 - 08:00 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

an fingerpints be lifted from a card and a piece of paper and be matched?
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Steve Howard
Posted on Thursday, January 24, 2002 - 03:13 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Graham

Although I personally don't know how many other bureaux conduct f/pt comparisons directly from a photographic negative, it is a practice that we do here in my bureau. In most cases, the latent print would most likely have been developed with CA, DFO or a white powder for example, producing black ridges on the photographic negative.

In this case, producing a tonally reversed final photograph showing black ridges instead of white, usually requires a second plate process, making a second negative from the original. The second negative being used to produce a final photograph with black ridges.

Those of you familiar with this process know how time-consuming this can be, especially if you are working with a large number of prints. Add to that the extra photographic supplies required and additional costs and itís easy to see the benefit of working straight from the negative.

In my own casework, I routinely work directly from negatives. Only when I have to take a fingerprint(s) to court will I utilize the second plate process for the purposes of making a chart, or if I'm required to produce photos of all my evidence.

Conducting comparisons with negatives usually necessitates use of some kind of light box. In our office, we modified one of our comparators by simply removing the left hand plate and replacing it with a small home made translucent box, which was seated on the adjustable support. The left hand fibre optic lamp was repositioned and secured underneath the box for transmitted light to create a mini light box large enough to support a 4x5 negative.
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Graham Ford
Posted on Tuesday, January 22, 2002 - 11:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Can you help?
I am trying to ascertain the frequency/normal practice within latent bureaux to conduct latent comparisons direct from the negative without procesing the negative to obtain a resultant photograph, i.e., hold the negative up to a light source and then subsequently compare with nominated suspect fingerprint cards.
Do examiners prefer this method, or do you prefer (? policy/protocol requirement) comparing from a correctly developed photograph (excluding latent lifts).

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