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.
...it was not that easy but I think I managed to analyse the pattern of the canvas on which Diego Velázquez painted 'The Supper at Emmaus'. a painting in the MET New York.