The disclosed invention pertains to latent fingerprint development, in general, on absorbent surfaces, and more specifically, to make visible latent finger print images of friction ridge material on porous surfaces thereby facilitating comparison of evidence with known finger print images. The preferred embodiment utilizes a contact dry ninhydrin treatment of porous surfaces which are heated by external electromagnetic radiation, such as that obtained from an ordinary microwave oven, to elicit fingerprint images visible without the need for organic solvents or alternate light sources.