AGLIONBY, William, Painting Illustrated in Three Diallogues. Containing some Choice Observations upon the Art. Together with The Lives of the Most Eminent Painters From Cimabue, to the time of Raphael and Michael Angelo. With an Explanation of the Difficult Terms, London, John Gain, 1685.1 quotations
What is properly the Colouring of a Piece of Painting ?
It is the Art of employing the Colours proper to the Subject, with a regard to the Lights and Shadows that are incident to the Story, either according to the Truth of it, or to the Painter’s Invention : and out of the Management of these comes all the Strength, Relievo, and Roundness that the Figures have : ’tis hard to give Positive Rules here, it depending much on Practice ; but the most General is, so to manage your Colours, Lights, and Shadows, that the Bodies enlightned may appear by the Opposition of your Shadows ; which by that means may make the Eye rest with Pleasure upon them ; and also, that there be an imperceptible passage from your Shadows to your Lights.
’Tis generally observed likewise to make the greatest Light fall upon the middle of the Piece, where the principal Figures ought to be, and to lessen it by degrees towards the sides till it loose it self. In gentle Shadows, avoid strong Shadowings upon the Naked Members, least the black that is in them seems to be part of the Flesh. But above all, there is a thing called by the Italians, Il degra damento de Colori ; which in English may be termed, The diminishing of Colours : And it consists in making an Union and Concord between the Colours in the formost part of your Piece, and those that are behind, so that they be all of one tenour, and not broke ; and by this means every part corresponds with another in your Picture, and makes up one Harmony to the Eye.