"Cadmium red" is a term used to describe a specific shade of red color. It is called so because the pigment used to create this color contains cadmium. Full definition
When I came here [to South Carolina] and beg [a] n studying with Jean Pilk, who had studied for years with Daniel Greene, [she] directed me to use a palette of Cadmium Red light with Yellow Ochre as a base. (halsteadportraits.com)
Then I mixed a basic skin color of Cadmium Red Light, Yellow Ochre and Titanium White. (willem-art.com)