Latent fingerprints are what in relation to the naked eye?

• A. They are invisible to the naked eye
• B. They are visible to the naked eye
• C. They are always colored
• D. They are formed by dust

Answer: (A)

Latent fingerprints are invisible to the naked eye because they are just a very thin, colorless residue of sweat, oils, and minerals left by your fingertips on a surface. This residue doesn’t stand out under normal light, so you can’t see the ridge patterns without some processing. Investigators use visualization methods—like powder dusting, iodine fuming, or cyanoacrylate fuming—to make the pattern visible by creating contrast or color where the print is located. That’s why the statement about being invisible to the naked eye is the best description of latent prints. The other ideas aren’t accurate: latent prints aren’t inherently colored, and they aren’t formed by dust (dust is a technique used to reveal them, not what they are).