"My dear MacColl,
I daresay I muddled what I said about Impressionism last night and perhaps this is a clear definition of what I think Monet would mean by the word, "The observation of the colour and value of the image on our retina of those objects or parts of objects of which we are prevented by an excess or deficiency of light from seeing the surface or local colour."
Of course to a very astigmatic or abnormal eyesight the whole field of vision might offer phenomena for the notation of an impressionist, but to the average vision it is only in extreme cases of light and dark, that the eye is conscious of seeing something else than the object, in other words conscious of its own medium—that something else is what the impressionist tries to note exactly. . . .
Yrs. sincerely,
John S. Sargent.

31, Tite Street,
Chelsea, S.W.,
My dear Jameson, March 20th
I have been reading your book with great enjoyment, and feel as if my ideas and my vocabulary had gone through a very satisfactory spring cleaning and I like the opposition of your clear processes of reasoning and analysis as far as that will take one and the ultimate mystery that you lead one up to from the different directions. There is one point only that I should quibble at and that is your use of the word Impressionism and Impressionist, 

These words were coined in Paris at a particular moment when Claude Monet opened the eyes of a few people to certain phenomena of optics, and they have a very precise meaning which is not the one that you use them for, so that in the exact sense or to a Frenchman, [George Frederick] Watts' saying "All art is Impressionism" would be a misuse of words. "Impressionism" was the name given to a certain form of observation when Monet not content with using his eyes to see what things were or what they looked like as everybody had done before him, turned his attention to noting what took place on his own retina (as an oculist would test his own vision). 

It led to his doing 50 pictures of the same subject under varying degrees of light and the phenomena which he recorded would be more or less apparent when there was excess or deficiency of light and the fact that he is astigmatic accounts for his having an excellent subject for his own discoveries in this line. 

A person with normal eyesight would have nothing to know in the way of "Impressionism" unless he were in a blinding light or in the dusk or dark.

 If you want to know what an impressionist tries for (by the way Degas said there is only one Impressionist "Claude Monet") go out of doors and look at a landscape with the sun in your eyes and alter the angle of your hat brim and notice the difference of colour in dark objects according to the amount of light you let into your eyes—you can vary it from the local colour of the object (if there is less light) to something entirely different which is an appearance on your own retina when there is too much light. 

It takes years to be able to note this accurately enough for painting purposes and it would only seem worth while to people who would wear the same glasses as the painter and then it has the effect of for the first time coming across a picture that looks like nature and gives the sense of living—for these reasons Monet bowled me over—and he counts as having added a new perception to Artists as the man did who invented perspective. 

This observation or faculty does not make a man an Artist any more than a knowledge of perspective does—it is merely a refining of one's means towards representing things and one step further away from the hieroglyph by adding to the representation of a thing the conscious Will of the Medium through which one sees it. One of these days some genius will turn it to account and make it part of the necessary equipment of an Artist. 

For the present in its exact sense "impressionism" does not come within the scope of your considerations. Of course I agree with what you say, given the rough and tumble and un-Jameson like use of the word. 

You can make impression stand for whatever you like but not add-sm or -ist without being challenged by the astigmatic.
Yours sincerely,
John S. Sargent

"Impressionism it is only the immediate sensation. All painters were more or less impressionistic. This is especially a matter of instinct. All this is simpler than Sargent believed. The term Impressionism was invented by the satirical newspaper as ridicule, which angered Manet. I did a lot wrong, because I was a bad example of it. . . I needed to create a cooler sensation. Yes it is the fading and passing tones within a tone. It is a nuance, for example between blue and yellow. It is something that can only be expressed in painting. It is true that the sun decomposes everything.

"I remember for the first time meeting Sargent and [Paul] Helleu at the Rue de la Paix 1876. Sargent was making a fuss over me, saying, “Is that really you, Claude Monet?” Then he invited me to dinner. He wanted to take us to the Cafe de la Paix, and he had many friends with him. I suggested the Cafe du Helder, and requested a private room. Unfortunately there were several of my pictures there, I was embarrassed as we entered, ashamed that Sargent and the others might think it was because of my paintings I had brought us to Cafe Helder."