Hello.

Does it correspond to darkening degradation of pigments; is it related to lack of illuminated interiors of the times, or to focus attention to the intended image, or was it the background trend of paintings ?   Seems once I read about 'cleaning/brigthtening' those centuries old artpieces with surprising differences revealing original colors.

[Random dark images borrowed from the web]

 

24 minutes ago, Externet said:

Hello.

Does it correspond to darkening degradation of pigments; is it related to lack of illuminated interiors of the times, or to focus attention to the intended image, or was it the background trend of paintings ?   Seems once I read about 'cleaning/brigthtening' those centuries old artpieces with surprising differences revealing original colors.

[Random dark images borrowed from the web]

 

One has to be careful with restorations. The Sistine Chapel seems to have been ruined by careless restoration. But I don't know if these paintings you show were originally as dark as they appear today. I suspect they were, as the intent seems to be to "illuminate" the figures portrayed.

If I am not mistaken, at least some of the images display examples of chiaroscuro, a baroque/renaissance technique building on stark contrasts between light and dark. Usually dark backgrounds with characters or part of them exhibiting illumination as mentioned by exchemist.