What is a key feature of Physical Developer's chemical reaction?

The key feature of Physical Developer's chemical reaction is that it forms a colored deposit with sweat components. This method is primarily used to visualize latent fingerprints on porous surfaces by reacting with the moisture and other constituents present in perspiration. When the Physical Developer is applied, it creates a distinct colored deposit that outlines the fingerprint pattern, making it visible for photography and further analysis.

This approach is particularly valuable in forensic science because it can effectively reveal prints that are otherwise difficult to detect, especially when the original print is faint or obscured. The specificity of the reaction to the biological components of sweat is what makes it an essential tool in latent print examination. Other options do not encompass this fundamental characteristic of the Physical Developer process.