What is the primary purpose of using Sudan Black in latent print development?

Sudan Black is a dye specifically designed to enhance the visibility of latent fingerprints that are formed from oils and other greasy substances. When latent prints are deposited on non-porous surfaces, they typically consist of oils and other excretions from the skin that may not be easily visible. By applying Sudan Black, these prints can be visualized effectively, as the dye binds to the fatty components within the prints, creating a distinct contrast against the surface. This allows examiners to see the latent prints clearly, aiding in their examination and comparison.

The other options, while relevant to latent print development, do not accurately describe the specific application of Sudan Black. For instance, techniques to enhance visibility on porous materials usually involve different methods or chemicals suited for those substrates. Similarly, preserving fingerprints in clear solutions or lifting prints from textured surfaces requires other approaches tailored to those challenges. Thus, using Sudan Black specifically addresses the need to make greasy prints more visible, which is why it is the correct choice.