My mentor, R. H. Ives Gammell, inculcating Boston School thinking, used to refer to the "grand tradition of impressionism whose probity resides in respect for visual truth." He went on to point out that there are historically two styles of painting: one based on form and structural knowledge and the other on appearances; academia versus impressionism. The crucial one in learning to true your eye to nature, impressionism, is embedded in the conversations of DaVinci and further developed in Velasquez and Vermeer, and finally Monet. I like to think of it as the phonics of the visual world, which, like mastering the forty-four sounds of the English language enables you to read anything, gives you the ability to paint with efficiency and accuracy anything you see. (I personally find sight size not to be impressionistic. Using it creates serious limits and unnecessary disabilities but also bypasses the necessary relational thinking.) Today's orientation towards the knowledge based system at some ateliers, if employed without learning to see the visual impression, has different limitations - as the memory balks after a certain point.