Houghton Library has the manuscript from the 1400s, that has the small title part “Foliate borders”
I zoomed in on this illuminated manuscript fragment, and it just kept adding more detail. I remain very impressed with these. Right, this is a time where one ought to use those “download the whole image” kind of tools that does the zooming for you. Yes, dezoomify. Here’s a direct link, with the above document page filled in.
When zoomed all the way in, the little details in the gold foiling, the dotted lines, the multicoloured shadings all come out. Neat craft.
Source: “Houghton Library. pf MS Typ 995. Foliate borders : manuscript, [14–].”
It’s a fascinating zoom in, as you say: the tiny white dots, especially.