More good news: another editor has gotten into image restoration and doing really good work. The image above is a historic isothermal chart from 1823. Jujutacular ran it as his first restoration about a week ago. His first effort was impressive and it was a treat to see that he had gotten it from the New York Public Library website. The pool of resources for source material is broadening.
That represents quite a lot of cleanup. His effort really shows on the upper margin and far left. I was on the fence about the nomination--didn't want to rain on his parade yet thought the restoration could go even farther. Took a chance and offered to collaborate. It turns out he's a really good sport, eager to learn, and a joy to work with.
He had a version saved without the histogram adjustment. Smart fellow! We traded off on additional dirt and smudge removal; both of us applied masks to correct the uneven brightness. I added a perspective crop, patched in a margin at the lower right edge, and did the final tweaks with curves and color balance. Sometimes it's magical when the final work feels like a time machine. This was one of those occasions.
Per request, adding links to the full versions: