Rainbow effect on grays on Kindle Colorsoft after converting with KCC

[oncpnda]

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):

KCC version:

Amazon version:

Pictures taken with iPhone 16 Pro.

Thanks again.

[axu2]

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]

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

[oncpnda]

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]

@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]

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

[axu2]

It's pretty much a property of color eink.

• FR: Reduce rainbow effect on Kobo Colour koreader/koreader#11877

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.

• png slow with mobi #533