Related Experiment Video
Updated: Jan 27, 2026

Design to Implementation Study for Development and Patient Validation of Paper-Based Toehold Switch Diagnostics
Published on: June 17, 2022
Optimization of the development of latent fingermarks on thermal papers
Florine Hallez1, Pierre Ledroit2, Damien Henrot2
1University Pierre and Marie Curie, Paris, France; Forensic Science Laboratory of the French Gendarmerie, 5 boulevard de l'Hautil, BP60036 Eragny, 95001 Cergy Pontoise Cedex, France.
Abstract:
Thermal papers, commonly used for printed receipts or lottery tickets, are omnipresent in our everyday life. They are regarded as semi-porous substrates, and yet can be critical to analyze when looking for latent fingermarks due to their thermosensibility. The aim of this study was to investigate a development sequence that would better combine the adequate detection techniques in order to maximize the chances to develop latent fingermarks left on these substrates. Different methods of development have been compared on test substrates: black magnetic powder, Lumicyano™, thermal development, ninhydrin and 1,2-indanedione/ZnCl2. Whitening stages and thermal development have been focused on, tested and optimized. The results of these preliminary tests enabled the study of three development sequences. They have subsequently been compared to the one currently used in the Gendarmerie's laboratories and the best results have been provided during pseudo-operational comparative trials by one of these sequences, consisting in 6 stages.
Related Concept Videos
Thermal expansion and Thermal stress: Problem Solving
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
Thermal Strain
Thermal Expansion
Thermal Stress
Optimal Foraging
Temperature and Thermal Equilibrium
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...

