R.A.Y. (Rhodamine, Ardrox, Yellow) is a fluorescent dye stain. It's a potent combination often used by latent print examiners to enhance latent fingerprint impressions that have been previously developed with cyanoacrylate ("superglue fuming"). R.A.Y. offers superior visualization on non-porous surfaces, particularly plastics.
Equipment
- Fume hood or well-ventilated area: Due to the chemicals involved, proper ventilation is a must.
- Protective gear: Gloves, lab coat, and safety glasses are essential.
- Shallow dish or tray: Large enough to accommodate the evidence you are treating.
- Forensic light source: One with excitation wavelengths in the 415 nm to 530 nm range.
Ingredients for a 1-Liter R.A.Y. Solution
- Rhodamine 6G: 0.1 g
- Ardrox P-133D: 1.0 g
- Basic Yellow 40: 0.1 g
- Methanol: 1L (high purity)
Mixing Procedure
- Safety First: Don your protective gear and work in your fume hood or designated well-ventilated area.
- Dissolve Dyes: One by one, carefully dissolve each dye (Rhodamine 6G, Ardrox P-133D, Basic Yellow 40) into the methanol. It's crucial to dissolve each dye completely before adding the next one.
- Storage: Transfer the finished R.A.Y. solution into an amber glass bottle with a tightly sealed lid.
Latent Print Processing with R.A.Y.
- Cyanoacrylate Development: First, develop latent prints using the cyanoacrylate (superglue) fuming method.
- R.A.Y. Application: Submerge the cyanoacrylate-developed evidence into the R.A.Y solution in your shallow tray. Depending on the print development, immersion can range from seconds to a few minutes.
- Rinse: Gently rinse the evidence with distilled water to remove excess R.A.Y.
- Dry: Allow the evidence to thoroughly air dry.
- Visualization: Examine the evidence with your forensic light source. Excitation wavelengths between 415 nm and 530 nm are ideal. The R.A.Y.-developed fingerprints will fluoresce with exceptional detail.
Storage Requirements
- Light Protection: The amber glass bottle is for light protection. Store R.A.Y. in a cool, dark place away from any sources of light.
- Temperature Control: A cool environment is best to maximize shelf life.
Shelf Life
R.A.Y. has a shelf life of approximately one to two years when stored correctly. However, it's wise to periodically test it for effectiveness.
Important Notes:
- R.A.Y is a powerful tool but can be messy. Background staining can occur, so monitor the development process closely.
- Always dispose of R.A.Y. and other chemicals according to your laboratory's hazardous waste protocols.