What are the two categories of surfaces for latent prints?

What are the two categories of surfaces for latent prints?

• A. Wet and Dry
• B. Porous and Non-porous
• C. Soft and Hard
• D. Large and Small

Answer: (B)

Latent print processing hinges on how a surface interacts with sweat and oils. The two categories used to describe surfaces are porous and non-porous. Porous surfaces, like paper, cardboard, and unsealed wood, absorb moisture and can cause prints to diffuse into the material, so chemical development methods that penetrate the surface (such as ninhydrin or DFO) are used to reveal the prints. Non-porous surfaces, such as glass, metal, plastic, or finished surfaces, don’t absorb moisture, so the print sits on top and is best developed with powders or by cyanoacrylate (superglue) fuming to make the ridge detail visible. The other options don’t capture this practical distinction used for selecting development techniques.

Latent print processing hinges on how a surface interacts with sweat and oils. The two categories used to describe surfaces are porous and non-porous. Porous surfaces, like paper, cardboard, and unsealed wood, absorb moisture and can cause prints to diffuse into the material, so chemical development methods that penetrate the surface (such as ninhydrin or DFO) are used to reveal the prints. Non-porous surfaces, such as glass, metal, plastic, or finished surfaces, don’t absorb moisture, so the print sits on top and is best developed with powders or by cyanoacrylate (superglue) fuming to make the ridge detail visible. The other options don’t capture this practical distinction used for selecting development techniques.