Trường Bộ Kinh (Digha Nikaya) 1:628
SUJATOEvameva ajjhattaṁ arūpasaññī eko bahiddhā rūpāni passati odātāni odātavaṇṇāni odātanidassanāni odātanibhāsāni.
In the same way, not perceiving form internally, someone sees forms externally that are white, with white color and white appearance.