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Figure 1.

Motivating principles and setups for multispectral petrographic imaging with both reflected and transmitted light. (A) The addition of bands within the sensitivity range of a standard optical sensor allows for the sampling of distinctive spectral characteristics, such as the hematite peak and trough near 750 nm and 850 nm, respectively. (B) Ultraviolet (UV) fluorescence is an informative source of contrast when studying materials responsive to UV light, like the apatitic and organic components of this fish fossil (from Tischlinger and Arratia, 2013). (C) Traditional cameras filter incoming light to just red, green, and blue signals, limiting spectral range and reducing the spatial resolution of each color. We use narrowband lights (one at a time), which allows us to capture signals from the full range of sensitivity, and at the full resolution of the optical sensor. (D) Photograph of our setup. RGB—red-green-blue; VNIR—visible to near-infrared.

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