Mixing Colors & The Artist's 'Sanctum Sanctorum'

"The order of Stuart's palette was as follows: Antwerp blue, Kremits-white, vermilion, yellow ochre, lake, Vandyke brown (with him a favorite color), and burnt umber--the latter used sparingly. All these colors were mixed more or less with white. He never glazed his pictures, nor ever attempted in this way to strengthen his shadows, for he thought it a trick. He was always particular to keep his palette in order, and if an artist brought to him one that was not up to a proper standard, he would address to him words clearly expressive of disapprobation. He also took great pains with his pencils, and would never allow any one to touch his easel, or its surroundings; indeed, during the latter years of his life he would never allow any one to go into his painting room when he was not present. If any one touched a pencil, or moved a picture, he would be sure to find it out; so that it became a settled thing in the house that it was best to abstain altogether from going into his sanctum sanctorum, unless invited to do so."

as related by the daughter of the Artist in The Life and Works of Gilbert Stuart by George Mason, Charles Scribner's Sons, New York, 1894, p 39