Rhodamine 6G
Definition
A fluorescent dye applied as a post-treatment to cyanoacrylate-developed fingerprints; excited at 530 nm (green), it emits at 565-590 nm (yellow-orange), greatly increasing contrast when examined under ALS through a matching barrier filter.
- Dye type
- Xanthene fluorescent dye
- Excitation wavelength
- 488-530 nm (green light)
- Emission color
- Orange-red to yellow-orange
- Application method
- Dipping or spraying after cyanoacrylate fuming
Common questions
What is Rhodamine 6G used for in fingerprint analysis?+
Rhodamine 6G is a fluorescent dye applied after cyanoacrylate fuming to enhance the visibility of developed fingerprints on non-porous surfaces. It makes prints glow brightly under alternate light sources, dramatically improving contrast against the background.
How does Rhodamine 6G work under alternate light examination?+
The dye absorbs light at specific wavelengths (around 488-530 nm green light) and fluoresces bright orange-red or yellow-orange emission. Examiners use matching barrier filters to isolate this glow and capture high-contrast fingerprint images.
Is Rhodamine 6G the standard dye in fingerprint labs?+
Yes, it is the most widely used post-fuming fluorescent dye in UK, Australian, and North American forensic fingerprint laboratories. It works consistently on cyanoacrylate-developed prints and is typically applied by dipping or spraying after the fuming step.
Related terms
- Alternate Light Source (ALS)
- A device emitting light at selected wavelengths (typically 415 to 535 nm) used to detect biological fluids that fluoresce or absorb light...
- Crime-Lite
- A compact, battery-powered alternate light source system (Foster+Freeman) designed for scene use by scenes-of-crime officers; the Crime-lite 82S and ML2 are standard...
- 1:1 Macro Photography
- Photography at a reproduction ratio of 1:1 (image sensor size equals subject size); the mandatory standard for all latent fingerprint photography before...
- AFIS Workstation
- A dedicated computer system with encoding software and database connectivity used by fingerprint examiners to encode latent minutiae, submit searches against criminal...
- Ardrox
- A commercial fluorescent dye mixture (originally for aircraft-skin crack detection) that fluoresces broadly under 365 nm UV illumination; used as a post-CA...
- Bandpass Filter
- An optical filter transmitting a defined wavelength range (typically 20-40 nm FWHM) while blocking all others; the excitation filter in an ALS...
- Barrier Filter
- An optical long-pass filter placed over the camera lens and worn as goggles by the examiner during ALS examination; blocks the excitation...
- Basic Yellow 40 (BY40)
- A fluorescent dye (excitation 450-490 nm, emission ~530 nm) applied immediately after CA fuming with a simple aqueous rinse to remove excess;...
- Chain of Custody
- The documented chronological record of who collected, handled, transferred, and examined a piece of evidence. For digital evidence, chain of custody includes...
- Cyanoacrylate (CA) Fuming
- The development of latent prints on non-porous surfaces by exposing the item to ethyl or methyl cyanoacrylate vapour in a humidity-controlled environment;...
- Cyanoacrylate Fuming
- A fingerprint development technique in which ethyl cyanoacrylate vapour polymerises onto eccrine sweat residue on a latent print, producing a stable, white...
- DFO (1,8-Diazafluoren-9-One)
- A fluorescent ninhydrin analogue used for latent fingerprint development on porous surfaces; excite at 450-470 nm (with secondary absorption extending into the...
Explained in these topics
- Cyanoacrylate Fuming, Alternate Light and Fluorescent StainsA xanthene fluorescent dye (excitation ~525 nm, emission ~555 nm) applied by dipping or spraying after CA fuming; the most widely used post-fuming dye stain in...
- Forensic Light Sources and Alternate Light ExaminationA fluorescent dye used as a post-treatment on cyanoacrylate-fumed fingerprints on non-porous surfaces; excite at 488-530 nm, bright orange-red emission.
- Lab Equipment and Chain of Custody for Fingerprint CaseworkA fluorescent dye applied as a post-treatment to cyanoacrylate-developed fingerprints; excited at 530 nm (green), it emits at 565-590 nm (yellow-orange), great...