What techniques have been suggested for recovering latent fingerprints on human skin?

The correct answer indicates that two techniques for recovering latent fingerprints on human skin have been suggested, which reflects the versatility required for dealing with different conditions and surfaces.

Magnetic powder is a commonly used technique that allows for effective visualization of latent prints on porous surfaces, including human skin. This method leverages the ability of the magnetic powder to adhere to the fatty residues and moisture left behind by the fingers, making the prints visible for further analysis.

The iodine-silver plate transfer is another effective method. This technique utilizes iodine vapors that adhere to the oils and sweat present in latent prints. After exposure, these prints can be transferred to a silver plate for visualization. This method is particularly useful because it can reveal prints that may be difficult to see using other techniques.

Both methods encompass different principles and applications, showing the diversity of approaches needed for the recovery of latent fingerprints on unique surfaces such as skin. This option captures the idea that multiple techniques are often necessary to achieve the best results in fingerprint recovery.