2014/2015 Daniel Rahn Grant Recipient

2014/15 Recipient
of the
Daniel Rahn Memorial Research Grant

Tess Mercer
Royal Melbourne Institute of Technology
Melbourne, Australia

Investigating Fabric Dye Influence on the NIR Detection of Bloodstain on Dark Clothing

1.1 Statement of problem
The forensic analysis of a crime scene relies heavily on visualisable evidence such as bloodstain patterns.  Bloodstains and bloodstain patterns on dark fabrics are generally difficult to visualise.
In recent years the use of near-infrared cameras to detect bloodstains has proven to be a viable, non-invasive technique. This technique allows Blood Pattern Analysts to easily interpret bloodstain patterns on dark fabrics accurately.   However, near-infrared is not reliable for all fabrics. Some fabrics absorb strongly in the near-infrared region which block the blood from view while other fabrics strongly reflect in the near-infrared region, camouflaging or masking the infrared absorbance of blood altogether.
Little research has been undertaken to underpin the science of near-infrared detection of bloodstains.
This project will investigate the influence of different pigments, dyes and finishes commonly used by the textile industry, on the ability to detect latent bloodstains on dark fabrics.
Thus a problem exists in that the suitability of near-infrared for detecting bloodstains on all dark fabrics and which dyes, pigments and finishes inhibit near-infrared detection is not known.

1.2 Hypothesis to be tested
Successful NIR detection of latent bloodstains is restricted by the similar chemical structures of the haemoglobin component of blood and certain dyes and pigments.