| Author | Message | ||
     Kasey Wertheim |
Bobby, I was quite surprised when I found out how long fingerprints could last on porous surfaces. As you mentioned, it does depend on many factors, but many chemical techniques used to retrieve latent prints target constituents which remain within the porous surface long after evaporation of the moisture. These constituents can last many years, as evidenced by a study in which palm prints were recently developed on paper contracts where the hands of Native Americans had been purposefully placed over 100 years ago. -Kasey | ||
| Bobby Vu |
Hi! I want to thank Kasey for his detailed reply to my question. I have been looking into other discussions and have found excellent answers! My next question is, "Generally, how long after one touches paper (porous substance) can a print still be found?" (I understand that this depends on a variety of factors including dry fingers, direct press of finger, number of people who have touched it since, etc.) THANK YOU! | ||
| Kasey Wertheim |
Bobby, I am also intrigued by this question! :) There are several intermingled questions in your post, and it would probably be best to answer each separately. First, does another person touching an item destroy someone else's latent prints already residing on that surface? The answer is not necessarily, but it could. It all depends on many factors involved in the second touch, as well as some factors involved in the first touch. For more, see the discussion in this same section entitled "Prints on top of each other..." You also mention a one year time span regarding the age of a latent print, and for that I will direct you to a couple of discussions directly answering your question at length. In the post "Length of time for fingerprints," Gary Jones gives an excellent description of what experts refer to as "subject" and "surface" factors involved in latent print longevity. For an outstanding discussion of environmental factors, see Wes Sossoman's post regarding "The effect of temperature on the constituents found in latent fingerprints". Both of these discussions can be found in the "General Questions from Non-Fingerprint Experts" section. Whether or not fingerprints are left by all people who have ever touched an item since its creation, depends on the conditions during each of those touches. When we consider useable latent prints as "chance" impressions, we realize that the likelihood of leaving a latent print depends on many factors taking place during the touch itself. If the finger is moving and just smears across the surface, no useable print will likely be left. If the finger is completely dry and void of residue or other contaminant, no useable latent print will likely be left even if the touch is ideal (straight down and back up). There are several answers to your intriguing questions! Clear as mud? :) -Kasey | ||
| Bobby Vu |
Hello. I was wondering if one left his/her prints on something plastic, and then others touched this item (e.g., a CD jewel case), and the original person hadn't touched it for a year or more, what is the likelihood of the original person's prints appearing after one year if tested for fingerprints? Also, when tested, would all the people who've ever touched that item since its creation's fingerprints appear? I would appreciate a reply, as I was intrigued by this thought. Thank you. |
