Final answer:
Amido black is a stain that targets proteins in latent impressions, aiding forensic scientists in the visualization of bloodstain patterns.
Step-by-step explanation:
Amido black stains the proteins in a latent impression. It is commonly used in forensic science for the visualization of bloodstain patterns at crime scenes. This dye has an affinity for proteins because it binds to the amino acids that make up proteins, which are often found in bodily fluids such as blood. After spraying or applying Amido black to a surface with a latent blood impression, the stained proteins become more visible, allowing for better analysis and documentation of the bloodstains.
The substance that amido black stains in a latent impression is protein.