I clearly recall being told in elementary school that the skin colors of dinosaurs are unknown because the necessary parts do not survive the fossilization process. I think that bothered me at first. I got over it eventually and had no trouble accepting that dinosaurs probably were similar in color to some selection of extant reptiles. Still that’s not as nice as knowing for sure.
Let’s put aside dinosaur skin color for now. Scientists have discovered pigments in the protofeathers of some dinosaur fossils. The new observations are of melanin-containing organelles called melanosomes, which exist in the feathers of birds today.
The two most common types of melanin found in modern birds are eumelanin, associated with black and grey feathers, and phaeomelanin, found in reddish brown to yellow feathers.
Both of these types melanin were seen in the fossils being studied.
National Geographic: Dinosaur True Colors Revealed for First Time.