Reflected and transmitted light microscopy
The distinction between reflected and transmitted visible light relates to the direction from which the light comes. Reflected light is directed from above the surface of the sample, falls onto the sample and is reflected, while transmitted visible light is illuminated from the bottom of the sample's surface of and essentially passes through the sample.
Samples taken from artworks for analysis using a vertical incision, which contain many layers, are usually examined using reflected light, while the analysis of fiber, fabric, paper, and pigment granules is done using transmitted light.
The information resulting from light analysis is referred to in optical microscopy.