The results found that ORO was able to produce high-quality finger marks, with excellent ridge detail, on a wide variety of wet and dry porous substrates. This study furthers the research conducted by Beaudoin by testing ORO on a wider variety of porous and nonporous surfaces, in addition to conducting further studies into optimizing the ORO formulation. Reformulation trials revealed the importance of the sodium hydroxide in the development of high-contrast fingermarks. None of the new ORO formulations tested produced results that were overall better than the original formulation provided by Beaudoin. ORO proved to be more effective on fingermarks less than four weeks old. ORO’s performance also declined with latent fingermark immersion time in water. These results could be due to the combined factors of mechanical surface interactions, the staining of diffused water-soluble components, and the degradation of the fragile fraction with time. Because of the degradation of ORO performance with time, it is not recommended that ORO completely replace PD as a routine regent, but rather be considered for latent fingermarks likely to be less than 4 weeks old. ORO proved capable of producing good-quality fingermarks in sequence with HFE- and HFC-based amino acid reagents. Because of the destructive nature of PD, it is suggested that ORO be used prior to PD in sequences for fingermarks on wet and dry porous surfaces. Tables, references, figures, appendix