Updated release: https://nyaa.si/view/1431539

Original release by Miss Dream and bloat removal by FitWeeb Repacks.

Here’s a lesson on why you should save non-colored images as grayscale.

There’s two ways of encoding color in a image: RGB and YUV formats. Let’s talk about YUV, which is what JPEG uses. So, YUV divides the image in three planes: Y, U and V.
The Y plane is called luma, it handles brightness and it’s saved at full resolution, since it’s more noticeable to the human eye. The U and V are called chroma and can be saved at various sizes, most commonly in half the size of the luma plane (YUV 4:2:0).

The original scans are YUV 4:4:4, which means all planes have the same resolution. But there’s a problem, you don’t need chroma planes in black and white images, they’ll just make the file size bigger. So, the person saving the images didn’t know nothing about color formats and did the most stupid thing that was saving them as JPEG, since PNG “is too big”. So whoever had the brilliant idea of doing this not only made the files stupidly bigger for no reason, but also reduced quality (not by much, thankfully). Props to Miss Dream for using wrong JPEG settings instead of exporting as grayscale PNG.

The process I choose was to simply convert all black and white pages to grayscale, saving them as png, and then optimize everything losslessly using pingo. (Shoutout to July for helping comparing other optimizers.)
Thanks to an anonymous user, it was detected an error in the first version where it wasn’t truly lossless. FitWeeb Repacks went immediately to solve the problem, this time with even better optimization!

Comparison

Tldr: compressed/optimized losslessly all of the pages of kanzenban volumes 01 and 02 of Sailor Moon, the only ones I could download.

Notes:

• Page 202 from volume 1 is rotated by 180° for some reason, which I didn’t fix. Mostly because I don’t give a shit, but there’s also dupes of that page
• The pages were poorly cleaned, so your cleaner should check that
• I’ve done some testing and I recommend you to use spline36 to downscale the pages to 2100px after editing them. Still a great resolution and gets rid of most of the aliasing. Photoshop’s bicubic smooth doesn’t do a bad job either in this case, but stay away from shitty scalers if you can.

FitWeeb, removing bloat from weeb shit since 2021.