It [grey color] makes no statement whatever... It has the capacity that no other color has, to make 'nothing' visible. To me grey is the welcome and only possible equivalent for indifference, non-commitment, absence of opinion, absence of shape (note 99).... but, grey like formlessness and the rest, can be real only as an idea.... The painting is then a mixture of grey as a fiction and grey as a visible, designated area of color.

p. 62, note 99-100 - 'Doubt and belief in painting' (2003)