Mauricio Chase*, Sarah Fieldhouse, Stephen Bleay and Neil Lamont
This review synthesizes current knowledge on the use of Acid Dyes (ADs) Acid Black 1 (AB1), Acid Yellow 7 (AY7), and Acid Violet 17 (AV17) identified by the UK home office as common enhancement agents for blood-contaminated fingermark impressions. Various factors which can influence AD bloodmark enhancement are reported in scientific literature, including sequence of application, time and temperature, dye formulation, substrate features, processing times and bloodmark volume, contaminants, fingermark age, deposition pressure and donor variation. While these dyes have demonstrated excellent capability on porous (excluding AY7) and non-porous substrates, this review has identified several gaps in understanding and application. Firstly, the effect of blood volume on the fixing and staining times of these dyes, particularly for marks associated with high volumes of blood, requires exploration. Additionally, factors such as air-to-surface temperature, substrate colour, composition, coating and degree of porosity need a comprehensive study to improve practitioner awareness and best practice capabilities. Research into the effects of temperature on AD staining times should also be probed to evaluate the performance and suitability of different dye formulations under operational conditions and their response to temperature fluctuations. Furthermore, examining the effect of proteinaceous and non-proteinaceous contaminants on blood mark visualisation substances is encouraged. Accurate modelling and regulation of deposition pressures and contact durations are also suggested to understand blood matrix responses and their influence on enhancement due to the likely impact on operational marks. Addressing these knowledge gaps will provide valuable insights, optimizing the selection and proficiency of AB1, AY7 and AV17 for blood mark application, thereby benefiting practitioners and researchers alike.
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Journal of Forensic Medicine received 165 citations as per Google Scholar report
