What is the primary reason for the loss of latent prints according to common causes?

The primary reason for the loss of latent prints often relates to the use of excessive powder. When too much fingerprint powder is applied during the processing of latent prints, it can overwhelm the details of the ridge patterns, making the print less distinguishable or even obliterating it entirely. Excessive powder can also lead to smudging or obscuring of the finer details of the print, resulting in the inability to make a positive identification. Proper technique in the application of fingerprint powder is crucial, as the goal is to enhance the visibility of latent prints without compromising their integrity.

In this context, insufficient brushing might fail to adequately reveal a print but is less significant compared to the impact of using too much powder. Lack of proper temperature or inadequate lighting conditions can affect the overall conditions in which fingerprints are processed, yet they are not as directly influential on the print's visibility and integrity as the amount of powder used. Thus, the correct answer highlights the critical aspect of proper powder application in latent print examination.