Show HN: Using 2D DFT, dithering, etc. to maximize eInk manga image quality | Hacker News Reader

Show HN: Using 2D DFT, dithering, etc. to maximize eInk manga image quality

github.com

76 pointsseam_carver20 comments

Kindle Comic Converter optimizes black & white (or color) comics and manga for E-ink ereaders like Kindle, Kobo, ReMarkable, and more. Pages display in fullscreen without margins, with proper fixed layout support. Output works great in KOReader.

Full details on what KCC does is in the readme with plenty of photos!

KCC has been under continuous development since 2012 and has code sign on both Windows and macOS. Also available on Linux.

-the current kcc dev

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KCC best features:

1) filesize optimization. Think 600 to 100 mb after optimization per volume depending on source and settings. Does it by downscaling and dithering from 256 to 16 shades of gray (e.g. 8 bit to 4 bit)

2) black level correction. You need pure blacks in eink. Dark gray looks ok on paper and normal screens but not eink. Does it with histogram manipulation

3) semi automatic 2 page spread joining. spreads can be autorotated or not.

4) rainbow removal on kaleido 3 color eink with 2D discrete Fourier transform

Comic books and manga are amusingly amount the least digitizable mediums as you have the choice of good resolution but an unpleasant reading experience with lit screens on a desktop, laptop, tablet or phone and low res or lack of spreads on an e reader. Even more so when you're missing out on colour.

I find laptops (let alone phones) fairly unpleasant for anything resembling a comic. You really need a 4k monitor at least the size of a physical page. That usually implies portrait orientation, and then a second one for spreads, at which point just give up and use a large format tv. Or better yet just stick to paper.

I also have this problem with the scientific literature. Tablets let alone ereaders just don't cut it.

What I've long wished for but it doesn't seem to exist is a high resolution full color epaper tablet the size of a hardcover textbook page with a sub-second refresh time. Not live video or anything, 500 ms or so would be bearable for quickly panning around a document.

Indeed, and my kindle scribe 2022 10.3” 64 GB is bigger than a physical manga volume. I couldn’t imagine using anything smaller

Shrug. I've read comics on a 7" eReader, scientific papers on 7.8". Rarely is there a real problem IMO, occasionally color charts are a problem on my B&W reader.

I have slightly more sympathy for scientific papers due to smaller text and overall extra density but considering that it's pretty common for comic publishers themselves to release editions smaller than a typical 10.25x6.6 page, you don't really need page size (e.g., Archie's digests, every manga tankobon ever, DC Compact Comics).

I read manga on my kobo elipsa 2e (10" 227 PPI, 1404 x 1872 resolution) often and find the experience quite good. I specifically got that e-reader since it has a big e-ink screen. Manga is mostly black and white anyway and the color pages get shown in grayscale, that works relatively well. I suppose traditional comics also work well since they have black text on white background the color to grayscale may cover some detail but should definitely be readable. most color comics and manga are printed in 300 PPI.

Ever experienced the bug where usb loaded kepub manga disabled bookmarks and annotations?

https://github.com/ciromattia/kcc/issues/704

I'm not satisfied with a grey scale screen given it doesn't work for 99% of comic books and a significant amount of manga (ghost in the shell, for example, has a large number of colour sections)

A lot of physical manga volumes reduce what would have been originally colour pages in the serialization to B&W anyways. Heck, it's verrry common for that to include the eBook edition even though it doesn't really cost them anything.

KCC has a feature to combine spreads that I added, I think it works pretty well, photos in readme.

After combining you can autorotate it or not, it’s an option.

I read a lot of manga and comic since my childhood but never even once in my life I have able to enjoy manga on tablet/mobile as much as I enjoy them as physical volume. But looking forward to use Kindle Comic Converter

I also read a lot of manga and comic, but for me the tablet is the ideal experience. I can't read hundreds of pages, while travelling, on physical volumes.

Yes, I agree, eink is so close to physical paper. I have shelves of physical manga but eink is close enough to that experience for me.

Comments on a previous ShowHN, https://news.ycombinator.com/item?id=43916956

Hi, Could this have been a KOReader plugin too where all this processing etc is done on KOReader/Kindle itself instead of another machine?

There are a lot of koreader plugins that implement individual features. Any in particular you want?

But I prefer to preprocess on a pc to maximize ereader battery life.

Mainly the improved quality of images look most interesting to me.

KOReader has built in contrast and dither options that may do what you want.

And a rainbow removal plugin which uses same method.

I used to use KCC when I had a Kindle and it was great ! But now that I have a android based e-reader, I use Mihon

A lot of people still use KCC with non kindles for the file size and page turn performance improvements!

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