One reviewer commented that Rothko was able to "display authentic coloristic values". However, in the last years of his life he willfully reduced the gamma of colours to types of grey and blackish.
For Rothko, the canvas itself was ‘actor’, the ‘experience’ itself, and the spectator was expected to dialogue with it on an emotional level.
I especially liked the video on the Rothko Chapel in Houston, Texas. It has an octagonal shape with 14 paintings, with monochrome colours because it has all the silence required for intensive exposure.