The Theory of Effect: Embracing the Contrast of Light and Shade, of Colour and Harmony. E-book. Formato PDF John Bengo   -  Forgotten Books, 2017  - 

Without understanding these rules, a man, how ever well he may draw, can never be called an artist. Rembrandt, by his consummate knowledge of effect, gave that magic representation of light and shade, that raised him to the highest rank in his profession, which, with his deficient skill as a draughtsman, he could never hope to obtain.