The habit of breaking up one's colour to make it brilliant dates from further back than Impressionism - Couture advocates it in a little book called 'Causeries d'Atelier' written about 1860 - it is part of the technique of Impressionism but used for quite a different reason.
John Singer SargentAn artist painting a picture should have at his side a man with a club to hit him over the head when the picture is finished.
John Singer SargentI hate to paint portraits! I hope never to paint another portrait in my life. Portraiture may be all right for a man in his youth, but after forty I believe that manual dexterity deserts one, and, besides, the color-sense is less acute. Youth can better stand the exactions of a personal kind that are inseparable from portraiture. I have had enough of it.
John Singer Sargent