Content Kindle Comic Converter - Convert comics/manga to MOBI/EPUB

[DaleDe]

Originally Posted by Mondblut

Would grayscale conversion make any difference in terms of overall quality of the image?

It depends on the format of your images. JPG always degrades somewhat with every save, however saving to grayscale is highly unlikely to show any visible degradation. The grayscale itself, will convert to 256 levels of gray which is essentially continuous to the naked eye.

Most other graphics formats are not lossy formats however if you change the number of levels of gray you may see some difference, particularly if it is less that what you have. I would suggest you check the info on the image to determine how many gray levels there are in the image.

Dale

[Mondblut]

I tried to convert some manga and the quality of the (gamma converted) output on the reader looks much better than the "naked" jpg images on it. But i realised that in panels with alot of white backgrounds in it and only thin outlines of character faces, the panels seem alittle like overexposed old school fotos. On the other hand, detailed character portraits with alot of shading and graytones look really good. Same goes for character faces with thicker outlines. BTW: I`m using the Cybook Odyssey HD.
I don`t want to make wrong assuptions, but can it be that the tool was made for comics and not for manga in the first place? Therefore the gamma correction outputs the perfect gamma corrected pictures for comics (as they are colored in their native state and therefore have alot of shading compared to manga, where you oftentimes only have character outlines without much shading - that would explain the overexposed character faces on some panels).
I guess it would be nice to have a manga auto gamma correction feature.
Pls don`t get me wrong, i love the tool.

[AcidWeb]

This tool is not a magic wand. There are too many variables. Much depend on quality of source images. Creating auto gamma correction it is way out of scope of this application.

Currently when gamma option is set to auto color images are not touched at all. Black and white ones are hit with 1.8 gamma correction. For most of high quality source files this approach provide best quality on Kindle screens.

Additionally you using unsupported device and I'm not sure if it even can display this type of content correctly.

[Mondblut]

1. About the color images: When i don`t have "color mode" activated, as i understand it will convert the picture to grayscale... Will the auto gamma then gamma correct it in the process or not (if i have a color picture being processed with color mode of for instance)?

2. For my device (the Cybook Odyssey has the same e-ink display as the Kindle PW2) i use the Kindle PW 1/2 option as it is the only option that creates a flawless epub for my reader (all other options created pictures that are cut of in half). Is the gamma correction and othe parameters applied to the source material the same for all settings (Kindle, Kobo etc.) or are there differences with each device setting.

3. What custom gamma would you suggest i should try if my picture seems to be overexposed as i described (i`m not an expert when it comes to picture adjustment). Is 1.8 always set for gamma if i use auto gamma?

4. What about other manga fans? What settings did you find to be the best for the most "accurate" (compared to real manga) experience.

[AcidWeb]

1. When gamma is on auto color images will not be touched. Output palette don't matter.
2. Yes there are differences but they don't matter apparently in this case.
3. No idea.

[Mondblut]

OK, i think thats the reason, why my mangas look to "bright". So basically i need to convert my mangas to grayscale before i use KCC!?
Do you know any tool that can convert all images in a folder and subfolders into grayscale without disrupting the folder structure?

[AcidWeb]

When it is not at auto all images are processed.

[Mondblut]

So basically: If i have a manga that is not grayscale, i should hit the custom gamma box and set gamma to 1.8, to get the same result as if i had my manga in grayscale in the first place and had gamma on auto?!

[AcidWeb]

No.

If you have color input files and set 1.8 all files will be hit with 1.8 correction.
If you have color input files and set auto color files will be not gamma corrected, black & white ones will be hit with 1.8.

It is completely not connected with Color mode option.

Extensive testing showed that in most of cases gamma manipulations of color images decrease quality and readability on Kindle screen. That is reason why auto mode work this way.

[Mondblut]

My problem is: Even though my manga is not in color in general, it is still encoded with color information when i check its info in Irfanview... If i convert it to grayscale there is no difference to the naked eye. Thats something i realised with many manga on the web... Even though they are in black and white, the picture is technically in color.

[AcidWeb]

I'm aware. That is reason why KCC don't use this informations to detect if image is color.

[Mondblut]

Ah, great, so if my manga appears in black and white even if it is encoded in color (like in my case), KCC will gamma correct it am i right?
But i tried to use custom gamma on it now and it is a bit darker than with auto gamma...

[AcidWeb]

I can't help you. Experiment on your own.

[DaleDe]

Originally Posted by Mondblut

OK, i think thats the reason, why my mangas look to "bright". So basically i need to convert my mangas to grayscale before i use KCC!?
Do you know any tool that can convert all images in a folder and subfolders into grayscale without disrupting the folder structure?

You can use IrfanView. It has a batch mode that can do this and lots more. It is a free download for Windows. Check our wiki for more IrfanView

Dale

[Mondblut]

Yeah, i already tried Irfan view for that purpose, but the sharpening wasn`t looking that good on the ereader. I normally used the manga tool "MangaMeeya" on my windows 10 7" tablet for reading manga. The good thing about this tool that it had many filters, including a sharpening filter (Pixel Averaging Algorithm + weak/strong sharpening) for less high quality pictures, which made them look quite nice. I hoped sharpening would help with the the ebook reader as well, but it wasn`t the case. Still sharpening or contrast settings in KCC would be a nice addition, as sadly there isn`t always an ultra high quality version of a manga to be found, so having ways to enhance the source material in KCC would be amazing. Currently i`m comparing a manga that i physically own with the same manga on my e-reader. I still haven`t fould the best setup though.

Interesting enough the Kobo Glo mode in KCC looks a bit sharper than the Kindle PW 1/2 mode on my Cybook Odyssey HD, but i need to manually transfer/swap the image folder of the resulting epub to a in Kindle mode crated epub of the same manga, because the Kobo Glo epub presents the pitures "out of frame" on my reader. Of cause i set my gamma to 1.8 manually. Does the Kobo Glow mode actually convert/process the pictures with diferent parameters than the Kindle PW 1/2 mode?

Another thing that i noticed: Whenever the picture is higher than the native reader resolution, say 1200 pixels vertically, sometimes KCC crops so much away, that i need to activate the upscaling feature. Wouldn`t i be a nice idea to have an option for KCC cropping feature, that it never crops more away than the target resolution (say 1024 pixels vertically)? I`rather have smaller panels than a less sharp image due to upscaling, even though the source image has a higher resultion.