This document relates to a latent fingerprint imaging system. The system includes a light source that illuminates a sample surface having a raw latent fingerprint. The system further includes an optical detector arranged to capture fluorescence instantaneously from gap portions of the sample surface between ridges of the latent fingerprint and use the fluorescence from the gap portions to generate image data of the latent fingerprint on the sample surface. The light from the light source has a wavelength that is greater than a propagation threshold wavelength so the light can propagate from the light source to the sample surface and is less than an absorption threshold wavelength so the light is mostly absorbed by material of the latent fingerprint.