The idiot by GOYA 1797 - One of a series of 80 etchings called Los Caprichos which saw Goya begin to explore darker subjects including mental health, which would culminate in The Black Paintings, also on this board.
I want to try this for its lovely colour and tonal effects COLOR ILLUSTRATIONS by Zakhar Krylov, via Behance. Ink effects and photoshop tutorials - see tutorial links to Mr Talbot / Digital Art Wall. Search repetition in action of drawing, ink or paint.
Illustrator Florian Nicolle (previously) has published a wonderful collection of his textured illustrations from Layering scans of newspaper, ink, paint, and a fair amount of digital retouching he arrives at these truly remarkable portraits.