Дигха Никая 1:623
SUJATOEvameva ajjhattaṁ arūpasaññī eko bahiddhā rūpāni passati lohitakāni lohitakavaṇṇāni lohitakanidassanāni lohitakanibhāsāni.
In the same way, not perceiving form internally, someone sees forms externally that are red, with red color and red appearance.