Daubert relevance to Amido black?

[antonroland]

Hello all

A colleague asked me about this recently:

Is there anyone on here who can enlighten me as to the relevance of the Daubert criteria to the working of, say, Amido black or any other reagent for that matter?

My personal opinion is that Daubert is only really relevant to the greater methodolgy of identification / exclusion of identity in the comparison process and the fingerprint comparison methodology and not so much in the working of a reagent.

I am sure there are also many ways in which Amido black is used with different solvents, pre-mixes and applications but I would like to hear from anyone knowledgable in this.

Thanks

[Gerald Clough]

I think we have to look at any technique as being subject to Daubert. That certainly doesn't mean that a challenge will be laid for every process, but I can imagine that, if amido black enhancement featured in a piece of critical fingerprint evidence, the question could be raised. It seems to me that an enhancement method would be addressed separately from the subsequent analysis of the product of enhancement, since, if you can take down the method of producing data, attacking the analysis hardly matters. I take enhancement to be a class of imaging, a rendering visible of something that could not otherwise be observed. The relevant core questions are:

"Is the action of amido black on an occult deposit well understood in terms of which substances it reacts with to produce visible deposits?"
"Is its use to enhance fingerprint impressions by deposition of blood generally accepted as productive of such impressions?"
"Has it been tested in field use (including the crime lab as 'field')."
"Is the technique subject to meaningful error, producing an image of impressions that are not fingerprint impressions but cannot possibly be differentiated from fingerprint impressions?" (I'm not sure about that one, but it seems to me to be what could be meant by "amido black error.")
"Does the operator possess the training and experience to properly apply amido black to the problem of latent print enhancement."

These questions test the issues: (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.

Viewing Daubert properly as a junk science filter, it is relevant to any technique that produces something upon which an expert will testify. A challenge to any enhancement reagent should be a straightforward thing to deal with, but if such a challenge is granted a hearing, it must be met. Quite properly, an expert who depends on a product of some technique should have sufficient scientifically valid knowledge of the workings of the technique to demonstrate that the expert can put it to reliable use. Less than that leads to a situation that pretty well defines junk science.