| Author | Message | ||
     Ernie Hamm |
I do not know of a 'time standard' for waiting to dye stain a surface following cyanoacrylate fuming, but it should not be immediate. The universal permanence of a cyanoacrylate developed latent print is a myth because of variations in substrates, latent residue components and subsequent processing techniques. The solvents associated with various dye stains can affect latent print recovery. Any visible development following cyanoacrylate fuming should be photographed prior to the application of any dye-stain solution. | ||
| Thomas Konvicka |
Is there a standard for the length of time after superglue fuming till dye staining?? One thought is no. You can dye stain immediatley after fuming. The other I have heard is supposingly by a federal agency and that is you should wait 12 hours before dye staining a superglue fumed object. Reference source would be apperciated. Thanks | ||
| Ed German |
In theory it will make little difference, since most of the powder will wash off and only in a small percentage of cases should the contamination quench the luminescence sufficiently to cause you to miss a print under laser or alternate light source examination. In practice, it is a BAD habit for investigators in the field to super glue fume evidence and then powder it. The problem is that as much as 50% of the identifiable latent prints which we can find in the lab via laser or alternate light source will be missed by just powdering after super glue fuming. And, they are powdering after fuming to see if they need to take the time to submit it to the lab. If they don't see anything, they are not going to submit it (and that ignores the very good possibility that there are identifiable prints present that cannot be found with just dusting after super glue fuming). Investigators should merely fume evidence to stabilize the latent prints on nonporous evidence, then submit it to the lab (unless it's too large for collection/submission - in which case they will have to decide whether the evidence deserves the collection of 100% of the prints or just as many as they can find by super glue fuming and dusting). It is the same conundrum that occurs with investigators iodine fuming, or spraying documents with ninhydrin, in the field. They are doing it to see what's there, for they don't want to submit it to the lab if it's negative (plus everyone likes to say, "see what I found, what I developed in this case that might solve it..."). But, when an investigator processes a document with just iodine fuming or ninhydrin in the field and gets nothing, he is not going to submit it to the lab (after all, that could infer that he was perhaps wasting his time and that lab sequential processing using DFO, ninhydrin and Physical Developer would have developed everything he could have and even more). --Ed German | ||
| Patrick |
I had a question asked of me recently that I'm not sure of the answer. If you superglue an item, then powder it, does that affect the efficacy of subsequent dye staining? I suggested to the guy that if I were going to dye-stain it, I wouldn't powder it. But some of the officers in the field are fuming evidence, then powdering it, and subsequently sending it to the lab where they dye-stain it. So his question was, will the powder all wash off and will the dye stain be as effective as if it were not powdered? |
