developing latents on carbon paper

[Ernie Hamm]

I was wondering if the substrate in question was ‘carbon’ paper or perhaps NCR (no carbon required) paper like you encounter with receipts and such. I had no information on processing techniques for either paper.

However, on visible marks seen on the ‘carbon side’ of NCR paper, there may be other considerations. Pressure on the non-carbon side to the paper when a hard surface is against the carbon side can produce visible marks on the carbon side, but the marks’ features will be in a positive orientation to those in the object responsible for the mark. This has been seen in several cases involving footwear tracks found on paper receipts walked on during an incident, such as a robbery when credit card receipts have been tossed on the floor. This is similar to the same type of phenomenon seen in back-transfer of tread patterns to the inside of clothing upon impact of footwear or tire.

Is it possible that a latent (patent) friction ridge print could be a back transfer when encountered on NCR paper or even carbon sheet paper? There have reported instances in which a latent print has been developed on a surface touched by a person wearing latex gloves. If there is sufficient pressure and quality of friction ridge structure, which seems to be the case with latex glove transfers, it would seem a possibility.

If visible latents are observed on such items as carbon and NCR paper, it could be prudent to compare them in positive and negative position.

[gandolflundgren]

I have had many X-Ray Technician Jobs before and I know that wrapping an object with foil and then wrapping the foil with black cloth will beat an x-ray but will leave a void of an image in a container. Carbon paper doesn't seem like it would work because x-rays should be able to pass through them unlike foil. Unless the paper's density and color is good enough to beat it. Any who, I've never heard of that method before

[blackeyedgurl]

I've dealt with a lot of carbon paper in drug cases. I've had the best results with superglue. BUT superglue the hell out of it. It seems to take a little longer to develop on CP than it does on the plastic wrap it is so often wrapped with. A visual exam using side lighting with a flashlight will often be enough to bring up detail, but I've had better luck with dye staining for photography (there is usually a pattern on the non-carbon side and as it is usually silver it can really interfere with the print). I've used R6G in methanol, and examiner with a laser. If you get too much background you could always rinse with more methanol, but I've never had a problem with background developing. Lastly I usually powder it with grey/silver powder, but I've had no luck bringing up good quality prints, prints worth photographing, or any new development other than what I've gotten with the dye stain.

Doing the above I've also developed some ridge detail on the carbon side of the paper, but that is best captured as a superglue print in my experience.

It seems like a lot of the bundles we have coming in through Texas are being wrapped in carbon paper and plastic wrap, moreso than the disgusting red goo they used to be wrapped with. One recent batch had dryer sheets that smelled so lovely we wished we knew where they came from. (You know you've worked too many kilo cases when you start judging the dryer sheets). The carbon bundles seem more common with cocaine and the red goo seems more popular with marijuana.

~A

[SConner]

Just out of curiosity, how many layers are folks unwrapping when processing large bales or blocks of controlled substances? I haven't seen anything other than plastic wrap used for an outermost layer. I've smelled dryer sheets or fabric softener, but we typically don't unwrap or cut into them far enough to get to that layer.

[blackeyedgurl]

I unwrap all of it. Usually when I get the bundles the drugs have already been removed (an 'L' shaped cut usually does that) and I unwrap each and every layer. Our agencies are not just looking to show someone had the bundle in their possession (they rarely make it to their intended destination, as they are often intercepted), but to find the original source. The outermost layer is usually the most abused by the investigators, and I've rarely developed prints on the exterior of the outermost layer of the bundle.

I've had a lot of success developing prints on inner layers (including freezer bags, duct tape, carbon paper, bubble wrap, packing tape and even some usable prints on plastic wrap with the red goo), and I've ID'd several people through IAFIS who were not suspects on the cases. Although most of the time there are few ID's as I'm pretty sure most of the bundles are produced in foreign countries and run over the border.

I'll admit I hate working these cases, but mostly because I pretty much know I'm going to develop a lot of prints and that the case will easily take a month to work. The only real problem I see when working with these prints is you have to physically reverse all of them as I've seen more than one print transfer from one layer of plastic wrap to the layer over it.

~a