Read this: Rothko also began using the new synthetic pigments, but not always with happy results. In 1962 he donated to Harvard University a series of large murals of the Passion of Christ whose predominant colors were dark pink and deep crimson. He mixed mostly traditional colors to make the pink and crimson; synthetic ultramarine, cerulean blue, and titanium white, but he also used two new organic reds, Naphtol and Lithol. The Naphtol did well, but the Lithol slowly changed color when exposed to light. Within five years the deep pinks and reds had begun to turn light blue, and by 1979 the paintings were ruined and had to be taken down.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What organic reds did Rothko use in the Passion of Christ murals?
Naphtol and Lithol