Physical developer (PD) is a widely used chemical processing technique for the development of latent prints on dry or wetted porous surfaces. Part I of this research compared fresh and aged batches of PD working solutions using two nonionic surfactants, Synperonic N and Tween 20, and determined that PD working solutions incorporating Synperonic N had a shelf life ranging from 10 to 15 days; whereas PD working solutions incorporating Tween 20 had a shelf life of approximately two and one-half months. The objective of Part II of this research was to discuss the importance of reliability testing to determine the stability of a reagent and comparisons conducted between two different test solutions, gold chloride (AuCl3) and EDTA tetra sodium salt. This study determined that gold chloride test solutions degrade on Whatman #2 filter paper as well as in solution; whereas EDTA tetra sodium salt test solutions degrade much slower on Whatman #2 filter paper and appear to remain stable in solution. (Published Abstract)