CLPEX Chat Board

Hello all

Personally I have never seen anything like this...any of you?

Inside the red circle you will note a ridge making an abrupt turn of approximately 90 degrees and then another, apparently crossing adjoining ridges.

Any comments appreciated.

Substrate: car hood (curved)
Matrix: water and dust - wet at time of deposition of latent.

There appears to be some scarring nearby. Also, if there was a lot of moisture mixed with dirt between the skin and the surface it may have caused a bit of distortion if that particular area was the last bit to come off the surface.

Hi Ann

I agree about the scarring but I believe that the scarring is independent from the 90 degree turns in the ridge. If the turns are the result of distortion I am puzzled as to how and what kind of distortion caused it...the area surrounding the turning ridge structure seems to be OK and free from double depositions and slippage...the wetness of the hand and pollutants to the matrix both seem to have had an even result / influence on the latent palm.

A rather interesting ridge event no matter how I look at it...

Anton out of curiosity and so I do not have to guess.

What is the substrate and the matrix ?

Hello Charles

Sorry, I should have put more space between the image and the text I suppose but in reading your post again I realise your question might be interpreted in more ways than one...

Ashbaugh in "Qualitative and quantitative friction ridge analysis" crc press 1993 (?), in describing a bottom-to-top analysis of a latent uses the term "substrate" to describe the surface on which the latent is found and "matrix" to describe the substance with which the latent is deposited...this can obviously aqueous or sebacious perspiration, blood, paint or any substance on the friction ridge skin at the time of deposition of the latent which would leave a latent or patent reproduction of the friction ridge skin on the substrate...

Very likely not perfectly quoted but this is broadly a paraphrase of my understanding of the terms used (coined?) by him.

HTH

Anton.

Anton, your first impression was correct----I just did not see it (curved car surface with dust and moisture).

I have seen photos of ridge structure before that had been CA fumed on a piece of oily foil and then very soon after treated with a dye stain. Some of the CA fumed ridge detail lifted up and off the surface like strings.

It looked a little what you have posted but the color and intensity was different.

But now that I see that it was dust and dirt from a car hood, the CA fumed scenario wold not apply.

Two simple options which I beleive you have already considered: Distortion because of the type of matrix or substrate OR friction ridge disruption (scar). I kind of lean towards the last one.

You may just have a muddy/runny latent!!

There can be some speculation about how this came to be without knowing all the details, but there another possibility. The first consideration would be to determine if this is an additive latent (contact with the substrate transferred material) or subtractive (contact removed material from the substrate). Your scenario of “car hood with presence of dirt/dust touched when wet” could place this into the subtractive mode and the features are not friction ridge detail (FRD), but ridge furrow detail (RFD).

That is really immaterial because the detail has been made visible by some means. With any ‘development’ on a non-porous surface, the FRD/RFD has acquired three-dimensional properties. This may be extremely miniscule, but it is there. It is this property that makes developed latent prints more susceptible to damage and alteration whenever an outside agency interacts with the latent.

Charles mentioned the situation with the “non-destructive” nature of a CA developed latent. I am familiar with this observation about CA prints (but it was not oily foil, just regular tinfoil). What was not made clear is the latent was not destroyed and did not go away. There were parts/segments of the CA-developed FRD whose surface contact was negated by the solvent in a dye stain solution (outside agency) and these parts simply ‘broke away’ from the substrate. Some pieces drifted off on their own and some simply migrated to other areas and reattached to the substrate, thus remaining a part of the developed latent.

If (big IF) the features in your example are RFD made visible by the presence of dirt/dust and were subjected to moisture (outside agency), areas of the RFD could migrate to another position. A muddy/runny latent.

Charles Parker wrote:Anton, your first impression was correct----I just did not see it (curved car surface with dust and moisture).

I have seen photos of ridge structure before that had been CA fumed on a piece of oily foil and then very soon after treated with a dye stain. Some of the CA fumed ridge detail lifted up and off the surface like strings.

It looked a little what you have posted but the color and intensity was different.

But now that I see that it was dust and dirt from a car hood, the CA fumed scenario wold not apply.

Two simple options which I beleive you have already considered: Distortion because of the type of matrix or substrate OR friction ridge disruption (scar). I kind of lean towards the last one.

Thanks, I thought in hindsight I MUST have been right on the first interpretation...

There is a considerable amount of slippage to the one side of the latent. Judging by how the latent was left on the car hood I am of the opinion that the slippage was before the latent was deposited.

Ernie, I will attempt a sensible response to your post as well, the matrix did indeed compress to the furrows and so the thin dark lines of matrix is dust and similar debris compressed away from the (background / white) ridges.

I seem to want to discount both options proposed by Charles...although the disruption due to scarring is the more likely one in my mind...with a less than 5% probability as the ridge flow around the "elbows" seem to be intact and independent from the possibly scarred area...

Oh well, proof positive any old way would be to find the known print...