Dermal Ridges Or Casting Artifact?

[Guest]

I use Plaster Of Paris - for my casts. Why? Because the only difference I have found between POP/Ultracal/Hydrocal - is the strength of the cast after it has dried. That's it. I have never casted a track and had "artifacts" (in the field)... I can always have a copy made later if the cast is that great.

I have writtten 13 articles on this issue... The main issues I found that can contribute to "artifacts" are: Grain size of the substrate. Smaller grain size - the easier it moves under the weight of the casting agent - thus causing "artifacts" .. Another issue is the mixing of your casting agent. Don't mix with anything smaller than your hand - and do so slowly - being careful to not whip the casting agent. Doing so causes air bubble to be trapped within the casting agent, which in turn, can lead to "artifacts" as the cast sets up.

Bittermonk and I disagree on the use of a "fixative" - hair spray etc. He uses them, I do not. I have never needed to. I have casted my own dermals in volcanic ash - without the use of a fixative. So, why carry something you really don't need. But, if others are more comfortable using a fixative - if used properly - I don't see it as a cause of dermals.. UNLESS you are using a spray that is greasy - like non stick cooking spray.

Oh dang, almost forgot. ALSO - when mixing add the casting agent to the water --- not the other way around. Doing so will force the air out of the casting agent. Think I am wrong? Grab your bucket and add in water - then start slowly adding in the casting agent. Now watch as the air bubbles come up. You want to see that.

Let the water soak up the casting agent - then start to mix. I mix with my hand in a latex glove. Easy peasey LOL.

Edited July 22, 2012 by Melissa

[Guest]

Isn't it logical to conclude that a line of tracks like the London Oregon Trackway could show a number of prints with a dermal trait like a cut or scar? To claim that those traits were recurring "casting artifacts" would be a statistical longshot. The same principle applies to dermal ridges. The foot would remain essentially the same except for differences in flexion. To expect "artifacts" to remain the same in several prints is unrealistic.

[Guest Transformer]

The main point was to show dermals IN TRACKS, not in casts. The first link has such a demonstration (image #3)

http://l.yimg.com/ck...470_2362136.jpg

and again here

http://sasquatchinve...ootprint-cu.jpg

Dermals IN TRACKS cannot be the result of casting artifacts as the cast has not even been made yet.

The Dr title was a mistype by me...he's a forensic fingerprint technician by trade and I've been unable to find any CV that states he has a doctorate. His appelation at most might be "Officer" Chilcutt.

I know he still works with dermals, and has been mentioned elsewhere in this forum still maintains that certain casts of tracks show legitimate dermatoglyphics.

Let's assume that Tube's research is entirely valid, what does that give us?

That casting artifacts CAN occur, but not that they always DO occur, nor that they are the same as dermatoglyphics that a trained forensic examiner (such as Chilcutt) can tell the difference between.

How does a person decide that those are friction ridge marks caused by the impression of skin friction ridges into that soil? How do you know that those are not just ridges formed by the tacky nature of some types of wet/damp soils sticking to what ever made those tracks? What expert trained and experienced in Forensic Print Analysis viewed those tracks you refer to and reported that they were in fact friction ridge marks from skin?

Again, I would like to see the actual report made by Mr. Chilcutt regarding his findings. As I said in my post #25 I know people trained as Mr. Chilcutt make extensive notes and detailed reports as their professional reputation relies on being able to accurately explain and pin-point every detail so the lay-person can better understand it in order to make a judgement call. ( Which is the sole purpose of an expert's testimony in court)

[Guest Darrell]

I think the thing one has to remember is that it is easy to get finger and palm prints from most surfaces due to the oil our bodies produce that transfers from the hand to the surface. It is much harder to get "prints" from the actual impression the hand or foot makes in dirt or sand, especially after the prints have been exposed to the elements. So, go out in your dirt patch, make a print, and cast it and see if your own dermal ridges show up in the casts.

Edited July 23, 2012 by Darrell

[Guest]

There is some spacing relative to size to consider, you might want to find a really big hand, the bigger the hand, the bigger the ridges, the more likely to show. Its like the feet, bigger, heavier, better impression, better chance than a normal sized human print leaving as much detail.

[Guest Transformer]

^ The size of the patterns of the friction ridges may get larger but there is no evidence that the friction ridges are higher or the furrows are deeper in people with larger hands or feet. Therefore there is no difference in the depth of the friction patterns when placed into a substrate.

[Guest]

I think the thing one has to remember is that it is easy to get finger and palm prints from most surfaces due to the oil our bodies produce that transfers from the hand to the surface. It is much harder to get "prints" from the actual impression the hand or foot makes in dirt or sand, especially after the prints have been exposed to the elements. So, go out in your dirt patch, make a print, and cast it and see if your own dermal ridges show up in the casts.

This is something I always recommend. There are more than 50 thousand soil types in this country - and soil fine enough to capture dermal ridge evidence in one place, may not be good enough somewhere else. I used pumice and soil from Onion Mountain. I was able to capture my own dermal ridges in both. How do I know they were my dermal ridges? Because I stepped in clay first - to capture the detail of my own dermals for later comparison.

[Guest]

Transformer, size and weight are certainly going to affect the impressions, that's just common sense. As well as affect the size of the subjects dermal ridges. Your telling me a spider monkey's dermal ridges are the same size as a gorilla's? Or that if a gorilla stepped in the same soft substrate as the spider monkey, there is going to be no difference?

[Guest Darrell]

Basically yes. If a 5'7" 150 lb barefooted human made a print his dermal ridges would be no deeper or pronounced than if a 6'10" 300 lb human made the print. The larger individual would have a bigger foot print and the print would be deeper but the dermal ridges detail would be the same. A persons skin isnt thicker or deeper the bigger you get. If the substrate isnt condusive to printing it wouldnt matter how big or heavy the individual.

This is something I always recommend. There are more than 50 thousand soil types in this country - and soil fine enough to capture dermal ridge evidence in one place, may not be good enough somewhere else. I used pumice and soil from Onion Mountain. I was able to capture my own dermal ridges in both. How do I know they were my dermal ridges? Because I stepped in clay first - to capture the detail of my own dermals for later comparison.

Melissa, that does make sense to use the actual soil from the search area you might find tracks to see if the dermal ridges can be detailed in the cast and then have a control to compare the cast to.

[Guest Transformer]

Transformer, size and weight are certainly going to affect the impressions, that's just common sense. As well as affect the size of the subjects dermal ridges. Your telling me a spider monkey's dermal ridges are the same size as a gorilla's? Or that if a gorilla stepped in the same soft substrate as the spider monkey, there is going to be no difference?

I have no experience reading, discussing and collating reports of any forensic experts on spider monkey or gorilla friction ridges. I do have experience reading, discussing and collating reports of many forensic experts in human friction ridges. As far as humans Darrell has answered the question quite clearly.

BTW JohnC could you please tell me about your experience or knowledge about friction ridges in spider monkey or gorilla footprints? Thank you. Should be fascinating to discover the differences and possible similarities between the different primate friction ridges!

[Guest]

I don't think a whole lot of specific dermal ridge knowledge is required to understand the principals of "stamping" and size. The dermal ridges are going to be relative to the size of the hand or foot. The dermal ridges in a child are not going to be the same size as an adults, simply because the foot is smaller. If something is heavier, then its going to leave a deeper, more defined impression, generally speaking. Don't believe it? Go get a piece of clay, press your thumb into it, then have a child do it, then try using different amounts of pressure, and see how the detail varies.

[Guest Transformer]

I thought we were discussing the size of dermal ridges? Depending on the substrate different pressures might be needed to exhibit patent (yes, patent) evidence of friction ridges. The size of the friction ridge has nothing to do with it. A child might leave even better patent evidence of friction ridges because there has been less wear on the friction ridges. That goes for someone who always wears shoes as opposed to someone who goes barefoot alot. Finger friction ridges also can be worn down. The really neat thing though is that friction ridges always grow back unless there has been irrepairable damage to the stratum basale which would result in scar tissue.

edited to add a question for JohnC: Does an organ of a body get bigger because the cells get bigger or are there more cells?

Edited July 25, 2012 by Transformer

[Guest Peter O.]

A BF would not necessarily exert more pressure per square inch than a human being. This is something I've wondered about when people mention "deep" tracks; I did a back-of-napkin type calculation during an episode of Finding Bigfoot once when I was more skeptical LOL

Edited July 25, 2012 by Peter O.

[Guest]

Talk about blowing smoke, the reality is, the larger impressions, made by a larger foot, or hand, allow for potentially better detail of the dermal ridges, because they are bigger, and there is more space between the ridges, allowing for potentially better detail of the ridges. Period. That was the point, derailing it with useless semantics does not change the point. I was simply stating an obvious fact, distort it all you want, but it is what it is. Its simply common sense.

If you cannot grasp such a basic simple concept,I am certainly not interested in trying to explain it, or discuss it beyond that.

Edited July 25, 2012 by JohnC

[Guest Transformer]

^ About a hundred years of very specialized study accepted by science and the courts around the world all brought down by an anonymous poster on a sasquatch forum who cites "common sense" for his arguments.