Normally, what filter is used to photograph Ninhydrin-developed latent prints?

In the context of photographing Ninhydrin-developed latent prints, the green filter is used for several important reasons. Ninhydrin reacts with amino acids present in the fingerprint residue, producing a purple-blue color upon development. When photographing these developed prints, a green filter allows for optimal contrast and clarity in the images.

By using a green filter, the photographer can enhance the visibility of the purple-blue developed prints against the background, while reducing the impact of any ambient light that may wash out details in the latent prints. This is particularly useful as it helps to eliminate certain wavelengths of light that can interfere with the detection of the developed prints, thus presenting a clearer and more defined image.

The other filters (red, blue, yellow) do not provide the same level of contrast or effectiveness in isolating the colors produced by Ninhydrin, making them less suitable choices for photographing these types of prints. Therefore, the use of a green filter is essential in the proper documentation of Ninhydrin-developed latent prints to ensure detailed and recognizable images for analysis and evidence collection.