Reveal high contrast fingermarks whilst suppressing background interference. Despite the vast quantity of fingerprint treatments currently available, examiners continue to be frustrated by a number of ‘difficult’ substrates.

Multi-coloured and densely patterned backgrounds, reflective metal surfaces and substrates that fluoresce at the same wavelengths as common fluorescent fingerprint treatments, can prevent the successful imaging of fingerprints.

However, when dusted with fpNATURAL® infrared?fluorescent powders, interference can be removed to reveal high contrast prints.

Exploiting the IR fluorescent properties of plants and minerals

When seeking materials that would fluoresce in the IR, we initially took inspiration from nature, testing a wide variety of minerals and plant based powders for suitability. Excellent results were achieved using a modified blend of cyanophyta and a bright blue mineral pigment known as Egyptian Blue.

fpNATURAL® 1, a plant based fluorescent powder

Cyanophyta or cyanobacteria is a phylum of bacteria that gains its name through its blue/green colour. Often referred to as blue-green algae, there are approximately 2000 species of cyanophyta, the perfect blend of which meets all the requirements to produce an ideal IR fingerprint powder:

• Emits bright IR fluorescence under blue/red illumination

• Rich in IR fluorescent phycocyanin and chlorophyll

• Non-toxic, safe to use and handle, and easily applied with a zephyr brush

fpNATURAL® 2, a mineral pigment based fluorescent powder

Egyptian Blue, also known as calcium copper silicate or cuprorivaite, is best known for its use in ancient Egyptian artwork found on statues, tomb paintings and sarcophagi. A bright blue powder, when viewed in the visible spectrum, Egyptian Blue exhibits strong Near-Infrared fluorescence when illuminated with either Visible or Near-Infrared light. The fpNATURAL® 2 blend of Egyptian Blue offers unique advantages to the fingerprint examiner:

• Emits fluorescence under Near-IR illumination

• Produces a significantly high quantum yield in excess of 10%

• Ideally suited to covert applications (can be stimulated in the N-IR)