|Posted on Thursday, October 02, 2003 - 07:34 pm: ||
I did a quick experiment on a self-adhesive stamp on a Manila envelope using the following method: Using a hair dryer set on low heat and allowing sufficient time for heated air to 'soften' the adhesive qualities, I then used a pair of forceps to carefully peel back the stamp from one corner. I was able to remove the stamp without any attendant fibers from the envelope. I then processed the stamp using WetWop which is the latest powder suspension product similar to Sticky-Side Powder (SSP) and which is superior to SSP and crystal/gentian violet methods for latent print development on adhesive surfaces. I was able to get excellent latent print detail on the adhesive side. Granted, these prints were known to be on the adhesive side and the stamp was freshly placed on the envelope and these facts certainly contributed to my success. However, and because I conducted the comparative testing on WetWop for Lightning Powder Company, the WetWop powder solution should be the process of choice once the stamp has been removed. Removal of adhesive stamps, labels, etc., with the use of substances that work by dissolving the adhesive can result in the destruction of a latent in the adhesive if not done very, very carefully. The latent residue is being held in the adhesive substance and if it is dissolved by a releasing agent, the latent is lost. The use of a hair dryer or the steam method used by Steve allows for gradual release of the adhesive and the removal of the stamp.
As with all 'questionable' techniques, such as removing the stamp, try it first in practice and see how it works. But if are successful, I would recommend the use of WetWop instead of SSP. However, one benefit I found when I tested WetWop is that it can be used post-SSP or CV treatment and still give results. Good luck with your case.
|Posted on Thursday, October 02, 2003 - 02:25 pm: ||
I was able to develop some ridge detail with a self-adhesive stamp on a standard envelope. I left the stamp in place during the ninhydrin (dipped) process.
After taking photos, etc... of any detail on the envelope, I steamed off the stamp using a hot plate and some water.
I slowly worked back the stamp a little at the time, re-steaming as I went.
Once the stamp was removed, ridge detail was present having been developed with ninhydrin through the paper. There was not enough for it to be of value for comparison, however.
Anna S. Duggar
|Posted on Thursday, October 02, 2003 - 01:31 pm: ||
Hello, all! Has anyone had any experience with self-adhesive stamps on standard manila envelopes? I do not need to preserve fingerprints on the non-adhesive side, only the adhesive side. Colleagues here swear by UnDu, but say you cannot pull or scrape the stamps off the envelope. Letting the weight of the envelope or stamp naturally remove the stamp while treating with UnDu has so far proved unsatisfactory. I intend to progress to liquid nitrogen in the next day or two.
Once removed, is there a recommended method for development? I tend to prefer sticky-side powder or Gentian Violet, but worry that with the paper backing I may get more background than development.
Note: RUVIS has so far not revealed any ridge detail at all on the few stamps successfully removed.
Thank you so much for your advice!