The investigation of latent prints can be fundamental in resolving a criminal act. In addition to fingerprints, lipstick smears can be investigated. Traditional lipstick produces a print that is easily identifiable. However, lip prints made with long-lasting lipstick can be invisible, requiring reagents that are more sensitive than conventional materials to locate and develop the prints. This study analyzes the effectiveness of reagents that are generically called lysochromes (Sudan III, Oil Red O, and Sudan black) in developing recent as well as older latent lip prints on porous surfaces.