alternative methods
Posted: Tue Apr 18, 2006 9:47 pm
i was wondering what alternative methods people have used to collect plastic/mo(u)lded/impressed and/or etched fingerprints? and their sucess?
One that I hold in reserve but which has been effective in difficult circumstances is the BVDA Gellifter:
http://www.bvda.com/EN/prdctinf/en_gel_1.html
http://www.bvda.com/EN/sect1/en_1_2a.html
The following example is not exactely an etched print, but you will see the similar application.
One situation was a print deposited entirely as normal skin secretions, probably the usual mix of ecrine and substances transferred from other body areas, on a rather rough painted area on the top surface of a window sash. This was the typical uneven surface left when wood parts in a public facility accumulate several layers of paint. The Gellifter captured a very useable impression. If you haven't used this product, the surface is a slightly tacky gel with a mirror finish. Anything that disrupts the surface creates an image that can be recorded photographically when lit by a single, strong light source at 45-degrees.
Had the native impression not been so visible under strong light, I would have considered glue fuming in situ, which produces an ideal reverse etch for this process.
Since the surface is so readily disturbed, any finely etched or raised pattern can be captured. Photography is, of course, the proper first option for many things amenable to gellifter application, but I considered the window sash situation photographically practically impossible, both because of the physical layout and because the impression was so subtle, being purely deposited secretions. Dusting such an impression would have yielded the poor results common for exposed, somewhat uneven painted surfaces.