FINAL by: OSAC Program Office; Version 2, January 13, 2020 1 

OSAC RESEARCH NEEDS ASSESSMENT FORM

Title of research need: Hand Detail Comparisons Black Box and White Box Studies 

 

Describe

the need:

Forensic image analysts are often asked to determine if a hand depicted in a questioned 

image, such as those submitted in child pornography investigations, has characteristics 

visible to provide support for an opinion on the source (i.e. the degree of 

similarity/dissimilarity to a known hand). Black box testing would assist in the acceptance 

of this type of examination in court through measuring the accuracy of the source opinions, 

particularly when there are varying levels of image quality. The inclusion/addition of white 

box testing can help identify which specific features are used by analysts in reaching their 

opinions under both ideal and real-world conditions. The effect of image quality and the 

feature sets determined through these black and white box tests can then be incorporated 

into a standards of guide for photographic comparisons. 

Keyword(s): photographic comparison, skin detail, hand comparison, patterned evidence, image 

analysis

Submitting subcommittee(s): VITAL Date Approved: 28 June 2023

Background Information:

1. Does this research need address a gap(s) in a current or planned standard? (ex.: Field identification system 

for on scene opioid detection and confirmation)

To date, research on the accuracy of source opinions in photographic comparison has focused on facial 

identification. However, image analysts are often requested to examine images to determine whether the 

hand depicted in the submitted images can be attributed to a source (i.e. the degree of 

similarity/dissimilarity to a known hand). Such requests often stem from imagery that is submitted in child 

pornography or sexual assault investigations where a suspect’s face is not visible in the image. The VITAL 

subcommittee seeks to have multiple black box studies conducted to determine the accuracy of analysts’ 

opinions when conducting comparisons on submitted imagery with varying levels of quality. The standards 

of practice and strength of opinions developed by VITAL will be directly impacted by the results of such 

black box testing (e.g., strength of opinion may be moderated by lower quality images). Likewise, multiple 

white box tests should also be performed with varying degrees of image quality to help define the specific 

features that analysts use to form an opinion under different conditions. Classification of the usefulness of 

various features can be incorporated into the standards of practice for conducting a photographic 

comparison.
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2. Are you aware of any ongoing research that may address this research need that has not yet been published 

(e.g., research presented in conference proceedings, studies that you or a colleague have participated in but 

have yet to be published)?

We are unaware of any ongoing research; however, there have been several studies in recent years that 

have started to address the validity and reliability of photographic comparisons of hands. More research is 

needed to fully document the scientific basis and error rates for the opinions formed by analysts.

3. Key bibliographic references relating to this research need: (ex.: Toll, L., Standifer, K. M., Massotte, D., eds. 

(2019). Current Topics in Opioid Research. Lausanne: Frontiers Media SA. doi: 10.3389/978-2-88963-180-3)

SWGDE Technical Overview for Forensic Image Comparison; 

Malone, C., [2015]. Inter-/Intra- Observer Reliability of Hand Assessment Using Skin Detail: A Count-Based 

Method. Journal of Forensic Sciences. doi 10.1111/1556-4029.12824;

Malone, C., [2015]. Photographic Analysis Using Skin Detail of the Hand: A Methodology and Evaluation. 

Journal of Forensic Sciences. doi 10.1111/1556-4029.12670;

Slot, A. and Geradts Z., [2014]. The Possibilities and Limitations of Forensic Hand Comparison. Journal of 

Forensic Sciences. doi 10.1111/1556-4029.12542

Lancaster University, [2021]. H-unique: In search of uniqueness - harnessing anatomical hand variation. Hunique. 10/14/2021. https://www.lancaster.ac.uk/security-lancaster/research/h-unique/.

 

4. Review the annual operational/research needs published by the National Institute of Justice (NIJ) at 

https://nij.ojp.gov/topics/articles/forensic-science-research-and-development-technology-working-groupoperational#latest? Is your research need identified by NIJ?

No

5. In what ways would the research results improve current laboratory capabilities?

The research results would explore validity and reliability of photographic hand comparisons, including 

developing error rates related to the quality of images and determining the feature sets found to be most 

useful in photographic comparisons. For the purposes of these studies, quality could be defined by the 

percentage of the imagery that captures the hand or the number of pixels that capture the hand, and the 

number of perspectives of the hand (if multiple images are submitted). Other factors like overall 

illumination of the scene, contrast, and color fidelity could conceivably be incorporated. Quantification of 

these variables would bolster the basis for source onions by describing the variables and their impact on 

accuracy of analyses in controlled cases (white and black box studies).

6. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)?

The research would assist in determining which features of a hand are most useful when conducting 

photographic comparisons of the hand. Such research would also assist in determining what quality of 

imagery is needed for an examiner to reach an appropriate opinion. In addition, the study would assist in 

determining error rates for photographic comparisons of the hand.
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7. In what ways would the research results improve services to the criminal justice system?

The research would help determine the probative value of photographic comparisons of hand.

8. Status assessment (I, II, III, or IV): I

Major gap in 

current 

knowledge

Minor gap in 

current 

knowledge

No or limited

current research is 

being conducted I III

Existing current 

research is being 

conducted II IV

This research need has been identified by one or more subcommittees of OSAC and is being provided as an 

informational resource to the community.