FYI, I just re-processed the last two images here and the last one here. When the pages from the Austrian National Library archive include reproductions of continuous tone originals, I find that it’s not ideal to make the white areas too white. Yes, the more accurately one preserves the colour and tones of the illustrations, the more accurately one ends up preserving the stains on the paper, but whaddayagonnado? It’s a balancing act, unless one has the time and the skill to attempt a full-scale digital restoration of each page — which I do not! That being said, since the three images I’ve reprocessed are line art and text, I’ve decided that it makes more sense in those instances to attempt to produce a nice crisp image than to worry about preserving intermediate tones, so… STAINS-B-GONE!