Two possible translations:
Assiette (f.) = “layer,” could be “ground layer” of a painting, but not always. fol. 29v refers to an "assiette" of gold which would be surprising for an underlayer at that period of time. Therefore "assiette", also refers to the layer that is visible in the fond of a painting in a broader sense as opposed to the preparation underlayer (eg : layer of gold in the fond of an icon). Nicolas Misery 2015. Reply: L. de la Verpilliere 06/07/15: In our case I think it specifically meant ‘underlayer’. But I think there would be no contradiction to understand this term as you do since this underlayer was often visible as the "painting’s background" at the time. (see Velasquez’s backgrounds for instance, re-using the painting’s underlayer with light touches of another color)
Assiette (f.) = “plate" - like on p004r, p005v
Seems to be especially problematic on 4r
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