What type of materials does Silver Nitrate primarily respond to in fingerprint development?

Silver nitrate primarily responds to chlorides found in fingerprint residue, which is why the correct answer is the second choice. When silver nitrate comes into contact with chlorides, it undergoes a chemical reaction that results in the formation of silver chloride, a compound that appears white under visible light and darkens upon exposure to ultraviolet light. This principle of responding to salts, specifically halide salts like those containing chloride, makes silver nitrate particularly effective in enhancing latent fingerprints left on porous surfaces, such as paper.

In contrast, while oils, fats, and amides may be present in fingerprint residue, silver nitrate does not interact with these materials in the same way it does with chlorides, making them less relevant in the context of fingerprint development using this chemical technique. Understanding this specificity of the silver nitrate reaction is essential for effectively utilizing it in forensic fingerprint analysis.