When a person says, "I see a yellowish-orange after-image," he is saying something like this: "There is something going on which is like what is going on when I have my eyes open, am awake, and there is an orange illuminated in good light in front of me, that is, when I really see an orange."
John Jamieson Carswell Smart (b. 1920), Australian philosopher (Adelaide, Australian National University). The Philosophical Review LXVIII (1959): 167. The Philosophy of Mind, edited by V. C. Chappell, Prentice-Hall (1962), "Sensations and Brain Processes."