Red Oxide is a dull red compared to colours like Cadmium Red Medium but there are many times when this, more earthy sort of color, is perfect. There are many artists who only use earth colors plus Cobalt Blue, Mars Black, and Titanium White and they find that Red Oxide within the context of a subdued palette like this becomes a very bright red. Because it is both chemically and visually similar to many natural colors in soil and rocks, it is wise to use it as the first choice red for general painting.