The Duquenois-Levine test has long been considered the standard presumptive color test for cannabis. It is quick, simple, easy to use and utilizes relatively cheap chemicals. There are very few other compounds that give false positives. Traditionally, hydrochloric acid has been used as the acidifier in the Duquenois-Levine reaction. The main drawback with the test is its use of concentrated hydrochloric acid.
Hydrochloric acid gives off a strong odor.
The fumes tend to degrade nearby objects as well as any dropper bulbs that they come in contact with. I have been unable to find any record of any other type or concentration of acid ever having been tried in the place of hydrochloric acid. For the past three years I have tried various other acids in varying concentrations. Trace Evidence and Crime Scenes 1. This presentation will cover latent prints left in blood on cloth.