search

ciromattia / kcc

KCC (a.k.a. Kindle Comic Converter) is a comic and manga converter for ebook readers.
ISC License
2.79k stars 222 forks source link

Rainbow effect on grays on Kindle Colorsoft after converting with KCC #771

Open oncpnda opened 2 weeks ago

oncpnda commented 2 weeks ago

I've noticed that some grays have a rainbow effect on the Kindle Colorsoft. This doesn't ruin the experience, but it can be distracting.

I compared the same frame to a version from Amazon's official release and the rainbow effect on the Amazon version isn't as prominent. This issue happens with all compression settings (JPEG/PNG/mozJpeg)

Is there something wrong with my settings, or is this caused by something in the conversion process?

Here are my settings (6.2.1):

Screenshot 2024-11-04 at 9 28 18 PM

KCC version: IMG_8841

Amazon version: IMG_8843

Pictures taken with iPhone 16 Pro.

Thanks again.

axu2 commented 2 weeks ago

You may want to bring this up in a forum where more people can comment like MobileRead or Reddit since I don't have a CS12.

But it could be anything. Color eink has limitations with grayscales and screentones.

I've also heard that kindle cs12 has different color modes like "vivid" that I'm unsure are available for mobi manga. Amazon manga is KFX.

bust4cap commented 2 weeks ago

what does it look like if you deactivate color mode in the kcc settings?

oncpnda commented 2 weeks ago

Even with color mode deactivated, the grays have the rainbow effect. It is possibly just a limitation of the CS? Maybe I got one of the bad ones...

axu2 commented 2 weeks ago

@oncpnda is there a rendering mode toggle for vivid mode anywhere in the menu or Aa menu or control center via swipe from top of screen in book?

Rainbow sheen happens since color eink is just a normal bw panel behind a bunch of small red/blue/green stickers.

oncpnda commented 2 weeks ago

Yes, I forgot to mention in the initial post that it happens with both vivid and standard mode on low and high brightness.

axu2 commented 2 weeks ago

It's pretty much a property of color eink.

Interesting solutions discussed their. Blurring the image, using a profile with a smaller resolution, etc. I wonder if pw11 or scribe profile fixes it. @oncpnda

Maybe png would help? But png has a bug where it converts really slow rn.

AcidWeb commented 2 weeks ago

It is not a bug but another kindlegen limitation. If image file is too big or use format not supported by it then it is converted again and in general break everything KCC do.

There are good reasons why JPEG is default output. Every time when kindlegen is working too long on EPUB created by KCC mean that input was faulty.