DFO (1,8-Diazafluoren-9-one)/PD (Physical Developer)
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Both of these techniques are used on paper or cardboard items. Both techniques are best used through dipping or swabbing the piece of evidence. The evidence should then be placed into a chamber where the fingerprints will be allowed to develop. These techniques are utilized in much the same way as ninhydrin. These chemicals will also necessitate the use of an ALS or laser. The reaction is with amino acids, peptides, and protein contained in the print.
1.2- Indanedione Reagent is a chemical alternative for DFO in chemical processing for latent prints on porous surfaces and is generally utilized
Figure 5.37 Results from cyanoacrylate.
prior to processing with ninhydrin. Although DFO is an excellent reagent, there are certain limitations to the DFO method, such as the high cost. 1,2- Indanedione Reagent reacts with the amino acids in fingerprint residues and produces fluorescent products that render latent prints visible (Medtech Forensics).
MBD is a dyestain consisting of MBD dye, 4-(4-methoxybenzylamino)-7- nitrobenzofuran, in a mixture of organic solvents. MBD has been noted to be an excellent dye for cyanoacrylate-developed prints on nonporous objects.
Nile Red Dye Stain
Nile Red Dye Stain is often used after cyanoacrylate processing on multicolor surfaces. Nile Red is fluorescent when exposed to a forensic light source between 450 nm and 560 nm, making it ideal for use with a wide variety of forensic light sources (Evident).
Figure 5.38 Super glue fingerprint processing techniques. Example of a fuming chamber that is utilizing the technique known as CAE, common name: Super Glue. The fuming chamber method is a preferred method as it keeps the vapors generated by the CAE technique contained, preventing unintentional contamination.
Oil Red O (ORO)
Oil Red О (ORO) is a lipid stain that is used for enhancing latents produced by the lipids commonly found in foodstuffs, oils, cosmetics, and other fatty substances. Oil Red О has been found to be particularly useful in revealing latents on porous surfaces that have been wet, a process that normally removes the amino acids, salts, etc., which are the basis of conventional chemical processing methods. Compared with physical developer, the ORO technique is much less complex and gives results of impressive clarity and
Figure 5.39 Super glue fingerprint processing techniques.
intensity. Oil Red О is a very useful and successful method of latent development and is used last in the sequence of chemical development techniques (Medtech Forensics).
R.A.M. Dye Stain—Rhodamine, Ardox, and MBD
R.A.M. Dye Stain is a fluorescent stain mixture of Rhodamine 6G, Ardrox, and MBD. Use R.A.M. with a forensic light source after processing with cyanoacrylate. Particularly, it is useful in the enhancement of cyanoacrylate developed prints on plastic bags. R.A.M. enhanced latent prints are visualized between 415 nm and 530 nm, making it ideal for use with a wide variety of forensic light sources. Provided as a 32 oz. premix bottle or concentrate (mix concentrate with 1 L of solvent (Evident)).
Figure 5.40 Iodine fuming.
Figure 5.41 Ninhydrin on paper.
Figure 5.42 Spraying Ninhydrin on paper using a hood.
Figure 5.43 Sprayed Ninhydrin on paper.
Figure 5.44 Results of sprayed Ninhydrin.
Rhodamine Premix is a dye consisting of Rhodamine 6G dye in a mixture of organic solvents. Rhodamine has been noted to be an excellent dye for cyanoacrylate developed prints. Longwave UV, Laser, or ALS is a suitable light source in order to visualized dyed prints (Medtech Forensics).
Figure 5.45 DFO (Source: Adorama Camera Inc.).
Ardrox Dye Stain—Alcoholic Premix
This fluorescent spray is designed for enhancing latent prints that have been developed with cyanoacrylate. It provides excellent ridge detail when the latent print is saturated with Ardrox. Prints fluoresce yellow/green when viewed under a light source (Evident).