Based on danke-Empire release https://nyaa.si/view/1437871
The source is only x1350 with jpeg artifacts and not properly grayscaled, what I did is:
* Upscale 4x to x5400 with a ESRGAN model trained on 1.176M manga samples
* Fix black and white points
* Compress with oxipng or jpegoptim
Comparisons:
https://imgsli.com/MTg0OTY1
https://imgsli.com/MTg0OTY3
https://imgsli.com/MTg0OTU5
https://imgsli.com/MTg0OTY0
https://imgsli.com/MTg0OTYy