When using the electrochemical enhancement of latent finger print technique, there are certain factors that have to be kept into consideration (Science Daily, 2013). These factors include;
1. The underlying surface has be electromagnetic. In most of the cases, it has to be a metal surface.
2. The fingerprint has to be latent, i.e. it has to be invisible to the eye as they are less likely be wiped.
3. The fingerprint residue cannot be on a surface that has been contaminated with material that may prevent or block any electric current that is required to be passed through.
The electrochemical enhancement of latent finger print is a technique that visualizes fingerprint through the manipulation of the electrical insulation characteristic that is evident in the fingerprints (Science Daily, 2013). Since the fingerprint material will act as a stencil or mask, it will block any electric current that is passed through. The electric current will be used as a medium to deposit a coloured electro-active film. Since the technique tends to concentrate on the gaps that exists between the fingerprint deposits, a sequence of techniques can be applied to enhance the quality of the fingerprint extracted
A powder based technique can first be employed. This is where standard black powder is applied using a mop head squirrel brush (Beresford, Brown, & Hilman, 2011). This would provide a base where the coloured electro active film will be deposited as the standard black powder will not block any electric current and will additionally absorb the electro active film.
This can be further enhanced by the incorporation of fluorophore molecules within the electro active film. The fluorophore molecules re-emit a light of 3rd colour (Science Daily, 2013). This colour is re-emitted when it is exposed to any electromagnetic radiation for example, ultra-violet light. This will help in obtaining the best likely contrast to the underlying metal surface.
- Beresford, A. L., Brown, R. M., & Hilman, A. R. (2011). Comparative Study of Electrochromic Enhancement of LAtent Fingerprints with Existing Development Techniques. J Forensic Sci(53), 93-102.
- Science Daily. (2013, September 12). Increased IDs from ‘Hidden’ Prints On Bullets and Knives. Crime Scene Training. Retrieved October 7, 2013, from http://www.csitechblog.com/latent-fingerprints/