The Spanish, Italian and Portuguese Old Masters all painted on hand-woven patterned linen canvases. This 'first layer' has been given only sporadic study by art historians. I started deciphering the weaving draft of El Greco’s 'The Burial of the Count of Orgaz', in 2016. It recently culminated in authentic, hand-woven reconstructions of historic canvases.
textile samples from 1400-1500 in the Victoria & Albert Museum, i asked and received high quality pictures. They look so similar to the pattern of the canvases from Old Masters ( below a reconstruction of a canvas that Titian used, woven at Lab O )