On which types of surfaces is magnetic powder the most effective?

Magnetic powder is particularly effective on non-porous surfaces like tile and glass because it adheres well and allows for the easy visualization of latent fingerprints that might otherwise go unnoticed. The nature of a magnetic powder involves small iron particles that can be attracted to any surfaces with the residual oils or moisture left behind by a fingerprint.

While magnetic powder may be able to be used on hardwood floors, it is primarily utilized on surfaces that provide a contrasting background to enhance visibility. In environments like bathrooms or tiled areas, the non-porous nature ensures that residues can be lifted easily without being absorbed, making the retrieval of forensic information more reliable.

In contrast, surfaces like rough concrete and asphalt tend to be porous and uneven, which can impair the powder's effectiveness. Similarly, paper and fabric absorb residues often making it difficult to lift fingerprints without damaging the underlying material. Therefore, magnetic powder is not the ideal choice for those types of surfaces. Metal surfaces may allow for some effectiveness, but the presence of paint or uneven surfaces can hinder results. Thus, tile, hardwood, and bathrooms are where magnetic powders yield the best results.