"All the thought which in the course of my studies I have been able to give to the subject has led me to conclude that the ideal in Art is but the impressions made upon the mind of the artist by the beautiful or Art subjects in external nature, and that our Art power is the ability to receive and retain these impressions so clearly and distinctly as to be able to duplicate them upon canvas. So far from these impressions thus engraved upon our memory being superior to nature, they are but the creatures of nature and depend upon her for existence as fully as the image in a mirror depends upon that which is before it."
January 1, 1970
https://en.wikiquote.org/wiki/George_Caleb_Bingham