Forensic Science

 

 

 

Development fingerprints with fingerprints powders

Powdering is the application of finely ground, colored powder to a nonporous object to make latent prints visible. Powder clings to moisture, oil, and other residues.

 

 

 

 

Development fingerprints withcyanoacrylate fuming

Cyanoacrylate fuming is used to develop latent prints on nonporous specimens.

 

 


Development fingerprints: iodine fuming

Iodine fumes adhere to grease or oils on porous surfaces and appear as a yellow stain.

 

 

 

 

Development fingerprints with ninhydrin (petroleum ether base)

Ninhydrin is used to develop latent prints on porous surfaces. Ninhydrin reacts with the amino acids present in perspiration.

 

 

 

 

Development fingerprints: silver nitrate

Silver nitrate is used to develop latent prints on porous specimens. It reacts with the sodium chloride (salt) content in perspiration.

 

 

 

 

Detection of explosives: dinitrotoluene and nitroglycerin test

A sample that contains dinitrotoluene and nitroglycerin in reaction with 20 % tetramethylammonium hydroxide gives blue color with DNT and dark green if nitroglycerin is present

 

 

 

 

 

Detection of explosives: janovsky test dinitrotoluene and trinitrotoluene test

Dinitrotoluene and trinitrotoluene with potassium hydroxide form a compound with characteristic red color.

 

 

 

 

Detection of explosives: RDX test (thymol)

The presence of RDX is detected as a blue coloring of a solution when the sample reacts with thymol in the presence of ethanol and sulfuric acid.