This is my inaugural tutorial. The aim of this, and subsequent tutorials is to offer my knowledge and “expertise” to those who are looking for specific answers to specific questions.

This tutorial is going to cover how you create an EPUB or Mobi of a graphic novel or manga for your eReader. Your eReader could be a Kindle, Nook, iPad or any other variant.

The key is to make sure that your reader is supported by Calibre. But there aren’t that many devices that aren’t supported by Calibre

What You’ll Need

You’ll need several things for this tutorial:

  1. Some kind of graphic novel or manga in an electronic format (scanned, preferably)
  2. A computer (obviously). It doesn’t matter which operating system you use, since all of these tools (and indeed all eReaders) are operating system independent
  3. Three pieces of free software: GiMP, 7Zip and Calbre (download and install them, now. It’ll save time later).

First Things First

And now for the slightly boring but legal bit

This tutorial is provided “as is” and is meant to impart the working practises and methods that can be used to achieve a certain goal using modern computing equipment.

This tutorial does not contain links to web services where copyrighted material can be obtained.

This tutorial does contain the steps required to create an EPUB or Mobi file for an eReader using free, open source software.

What This Tutorial Assumes

I assume that you are able to navigate an operating system, install software, read and understand English and follow instructions. That is all. No advanced degrees in Computer Science should be needed.

Oh, I also assume that you have either:

  • a collection of images or
  • a zip file containing a collection of images

Step One – Checking The Images

Check that the images you have are numbered. They need to be numbered in the correct order.

For instance, if I was dealing with a comic book, I would make sure that the first page was named something like”<name of comic book>-01.jpg” and that the final page was named something like “<name of comic book>-32.jpg”

Assuming that the comic book was only 30 pages long, with a cover page and a final page, too

Here is a screen shot, showing you the format I mean. You’ll notice that this comic book has only three pages, and that they are saved as png files. To be honest, it doesn’t matter what file type the images are saved as, since they’re going to be converted into the correct format for your eReader any way.

A Folder containing some scanned comic book pages

A Folder containing some scanned comic book pages

The naming convention I’ve used here is slightly different, but as long as the images are listed in the correct order, then it doesn’t matter what naming convention you use.

Step Two – Resizing The Images

The next thing you might want to do is edit them. All we should have to do is resize and drop the DPI for the images.

Most scanned comic books, graphic novels and manga are in very high res. Ths is fine if we’re going to read them with one a computer (maybe using Comic Rack, or something), but not if we’re going to read them on an eReader; especially since most eReaders have a limited screen resolution and memory.

So, open the first image with GiMP. You should see something that looks similar to this:

GiMP being used to edit a page of a comic book

GiMP being used to edit a page of a comic book

The area that we’re going to focus on is the “Image” menu. Specifically, we’re going to look at the “Scale Image” tool within the “Image” menu exclusively.

The

The Scale Image tool within GiMP

The “Scale Image” tool has only a few options, and we’re only going to change three things at maximum).

The first thing we’re going to do is drop the “Image Size”; most eReaders have a maximum images height of, about, 1000 pixels. So, change the number in the box next to “Image Height” to 1000. You should find that the number in the box next to “Image Width” changes, too (if it doesn’t, then click on the chain icon on the right of the boxes for both “Image Height” and “Image Width”)

Next, we’re going to drop the DPI (Dots Per Inch) or Resolution of the image to acceptable levels for eReaders. Most high resolution images have a DPI of, around 200+. This means that there are 200 (or more) pixels per inch of the image. The higher the number the more pixels there are in the image(which boosts the quality). The only problem with this, is that high DPI images will take a long time to display (if they display at all) on most eReaders.

All we need to do here is change the value in the box next to “X Resolution” to 75 (my go-to number for eReaders, as it’s nice and small, but still retains a fair amount of quality). You should find that the value in the box next to “Y Resolution” should change to 75, automatically (again, if it doesn’t, then click on the chain icon on the right of the boxes for both “X Resolution” and “Y Resolution”)
The final step is to change the “Interpolation” to “Sinc (Lanczos3)” then hit the “Scale” button.

You’re computer will do some maths, then produce the scaled image. Save this image (Ctlr+S/Command key + S or File>Save) and you’re done.

Step Three – I Couldn’t Think Of A Catchy Name For This Step

Perform Step Two on each of the images. Come back when you’re done. I’ll wait here patiently.

Step Four – Creating The CBZ File

Done? Excellent. Now what you need to do is used 7Zip to compress the folder containing your comic book into a zip file. But we’re going to change it’s file type from .zip to .cbz

You can also use cbr, but cbz is a littler quicker at Step Five

Right. Navigate to the folder with your images in. Then go up one folder.

For instance, the comic book that I am using is one called “Beta!!” You can see the files for this in the following screenshot:

A Folder containing some scanned comic book pages

A Folder containing some scanned comic book pages

As you can see they are stored on my computer at C:MangaBeta!!

One folder up from that would be C:Manga That means I want to go to this folder. As can be seen here:

The folder that contains my scanned comic book files

The folder that contains my scanned comic book files

Next, we need to right-click the folder with the comic book images in (at least in Windows) mouse over “7Zip…” and select “Add to Archive…”

Compressing the scanned comic book files

Compressing the scanned comic book files

I’m using Windows here, so you’ll need to figure out how to compress a folder into a zip file on your Operating System if it is different to mine.

The compression options screen should come up:

The 7zip options for creating a compressed zip file

The 7zip options for creating a compressed zip file

Most of these options are fine as they are (check that your options match mine). The only thing that needs to be changed is the text in the box under“Archive:” (at the top of the window. The only thing we want to change are the final three letters. We want to change those to “cbz”

In my example, the text will read “Beta!!.cbz” as can been seen here:

The 7zip options for creating a CBZ file

The 7zip options for creating a CBZ file

Your computer will do some more maths and compress the comic book image files into a zip file, then turn that file into a cbz file.

Step Five – Adding The CBZ File To Calibre

This one is real easy. The file that we just created?

The folder containing my CBZ file

The folder containing my CBZ file

Drag and drop it into Calibre; this will add the cbz to your library of books.

I use Calibre to manage my kindle, and it’s an excellent program

Calibre, shortly after adding my CBZ file

Calibre, shortly after adding my CBZ file

As you can see, “Beta!!” has been added to my library, but it has no meta-data (or tags). Both your eReader and Calibre use meta-data to organise your library of books. Any books that are already on your eReader will have meta-data on there (that’s how it knows what the title of the book is, what the name of the author is, how many pages the book has, what page you are up to, etc)

Step Six – Adding Meta-Data To The CBZ File

You can skip this step if you wish, but I don’t recommend it

To add meta-data to your comic book, all you have to do is right click on it, mouse over “Edit Metadata” and click on “Edit Metadata individually”

Finding the

Finding the

Adding meta-data is as simple as clicking into a box and typing it in. If you want, you can use Calibre’s built-in tools to download the correct meta-data for you (you’ll need to have the isbn number, minimum, for this to work correctly) but I’m not going to show you how to do that.

Editing the Meta-data of my CBZ file in Calibre

Editing the Meta-data of my CBZ file in Calibre

When you’re done adding meta-data, click “Ok” to save the meta-data.

Step Seven – Creating an EPUB or Mobi

Right click on your comic book, mouse over “Convert Books” and click on “Convert books individually”

Your comic book might have moved down your list of books, if you have more than one. This is because Calibre will be sorting your library by the authors’ surnames

Finding the Convert Books tool in Calibre

Finding the Convert Books tool in Calibre

The conversion wizard should be shown. You only have to alter two things on this wizard. As can bee seen here:

Converting my CBZ file to an EPUB or Mobi in Calibre

Converting my CBZ file to an EPUB or Mobi in Calibre

Make sure that you tick the box labelled “Do not add a Table of Contents to book”

And make sure that you select the correct file format for your reader from the drop down menu. When you are ready, click “Ok”

Step Eight – Deleting The CBZ

Go back to the Meta-data window (read Step Six, if you can’t remember how)

In the top right of the screen, you should see “CBZ (some numbers)” and “MOBI(some numbers)” or “EPUB(some numbers)”

The part that I’ve called “some numbers” is the size of the file in megabytes

Deleting the CBZ file in Calibre

Deleting the CBZ file in Calibre

Simply click on the icon that has the universal symbol for “Recycling” to delete the CBZ file. Now click on “Ok”.

Plug your eReader into your computer and wait a few moments for Calibre to recognise it. You’ll know that Calibre has recognised your eReader because a new column will be added to your library called “On Device”.

With your comic book selected, click on the “Send to Device” button at the top of the screen:

Adding the EPUB or Mobie comic book to my eReader in Calibre

Adding the EPUB or Mobie comic book to my eReader in Calibre

In a few moments your new comic book will have been copied across to your eReader. When it has been copied to your device, a green tick will appear next to the book under the “On Device” column.

Now close Calibre and safely remove your eReader and voilà.

That wasn’t so hard now, was it?

Related Post

Jamie is a .NET developer specialising in ASP.NET MVC websites and services, with a background in WinForms and Games Development.

When not programming using .NET, he is either learning about .NET Core (and usually building something cross platform with it), speaking Japanese to anyone who’ll listen, learning about languages, writing for this blog, or writing for a blog about Retro Gaming (which he runs with his brother)


GaProgMan

Jamie is a .NET developer specialising in ASP.NET MVC websites and services, with a background in WinForms and Games Development.

When not programming using .NET, he is either learning about .NET Core (and usually building something cross platform with it), speaking Japanese to anyone who’ll listen, learning about languages, writing for this blog, or writing for a blog about Retro Gaming (which he runs with his brother)

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  • Handleme

    Very nice. Thank you very much. Would you be able to post the maximum image sizes of some popular ereaders? Like the Kindle 3 and 4 etc?

    • Sure, as soon as I get around to it I’ll edit the post to include the image sizes of some of the more popular devices.
      J

      EDIT: A quick Google search tells me that the maximum resolution for the Kindle 3 + 4 is 800*600. But the resolution I gave seems to work fine on them. You could always experiment if you find that resolution too low, or too high. Let me know how it goes.

  • sara

    I don’t see the option for “do not add chapters” to the book

    • Do you mean “Do not add a Table of Contents to book”? Because Calibre will only generate chapters if it detects that you want to add a Table of Contents.

      Even if you don’t check this option, it’ll still work. The reason I recommended that users check this option is because the table of contents is useless, as each page comes out as a chapter. If you can deal with that, then don’t worry about it. Me, being a slight perfectionist, I can’t deal with that.

  • Felicity

    It said failed to convert :S I tried with .cbz and then with .zip as well and both didn’t work 🙁

    • Are you using the latest version of Calibre? (It should inform you that there’s an update every Saturday/Sunday)

      In fact, which version of Calibre are you using? I’ll make sure that I’m on the same version and run through the steps to see what needs changing.

  • Frisco

    What image size would you recommed for an iPad 2? Also, is there any other way to re-scale various images simultaneously? Since i have over over 800 images that would be a single book, it will take a while to re-scale one by one. Thanks!

    • Well, the default screen resolution for the iPad 2 is 1024*786 so I’d be tempted to try that first. If it looks great, then keep it. If not try keeping the aspect ratio the same, but altering the resolution. For instance, if 1024*786 looks pixelated, try 800*600. Does that make sense?

      I’ve been looking into group re-sizing with the GiMP. Currently there are ways to do it, but most of them don’t touch the DPI or EXIF data. The problem with high DPIs is that the image size will be huge, it will look really detailed on a large screen, but for smaller screens (like those of eReaders/iPads), there’s no point. Also, the EXIF data (information about how and when the image was scanned or photographed), is useless in eBooks and only adds to the overall size. As an example, a 6 page eBook made of images, with 100 DPI and EXIF data could be 25% larger than an eBook with 72 DPI and no EXIF data.

      I might look into writing my own GiMP script for doing this. If I end up writing it, I’ll share it on here.

  • lac

    Great!
    The only problem for me is that the MOBI dont have the right cover…
    It seams that the conversion takes any ramdom image instead of the first one…
    Any clue?
    Thanks!

    • To be fair, I think that Calibre takes the first image in the set as the cover. If it doesn’t select the right image, however, on the “Edit Metadata” page, if you hit “Browse” under “change Cover”, you can assign your own cover (or one that you’ve downloaded)

  • lac

    thats the problem!
    Calibre takes the first image, but the kobo dont have the right cover.
    Even if i change the cover after generating the mobi, then i regenerate mobi to mobi, the right cover isn’t still displayed on my kobo… 🙁

    • Ah. In that case, I would try adding another image to the set (before you zip all the images together), but name give it a “0000” name. That way, it’ll appear at the front of the zip file, and your kobo should take it as the first image in the file.

      As an example, if you were creating an ebook of “Beta” (like in this post):

      1. Get the cover art from somewhere (probably Google Images, but whatever works for you).
      2. Re-name the image to “Beta-0.jpg”
      3. Put the Best-0.jpg file in the same directory as all the other images (it should get listed first in your directory if you are listing by file name)
      4. Zip all the files in the directory
      5. Re-name the zip extention
      6. Run it through Calibre and convert to whatever format works on your device

      Does that make sense?

      • lac

        It does!
        But i already tryed that, and it doesnt work :s
        I tryed with an image named covier.jpg too

        • cover.jpg would never work – although you’ve found that out already.

          I don’t know how the kobo reads metadata, plus I don’t know what format you are using (MOBI or ePUB) so I can only make guesses.

          By “cover” do you mean the first image that’s displayed when you load the eBook, or the image that is displayed on your main menu/”choose a book” screen?

  • lac

    so : i use mobi for comics, as cbz dont handle metadatas, and epub display a bar with the page number, so the size of the images is reduce.
    by cover, i mean the image displayed on the main menu/choose a book screen.
    The first image display is the right one (number 00 or 01).
    Thanks for your help!

    • I’m really sorry for the late reply. I’ve been looking into this a lot, and it turns out that the Kobo doesn’t really support Mobi.

      This device reads a wide array of formats including, EPUB, PDF, CBR, and many text based formats. It does have EPUB 3 support to render the complex Japanese characters and Manga. The one drawback is chiefly attributed to the suspended support of the MOBI format, which is a very Kindle friendly format

      It looks like you might be better off trying an EPUB format. I’d make sure that you have the latest version of Calibre before you start (they release an update every week), and make sure that you’re using the original files (rather than re-editing the files that you’ve already edited). I hope that helps a little.

  • iheartartichokes

    Doesn’t decreasing the image size and resolution make the images practically unusable? I can’t seem to make my images smaller (in pixel dimensions) without losing quality.

    • Basically, you’ve got a trade-off between resolution and overall size/loading times for each page.

      To be fair, your ebook reader will reduce the resolution of each page before displaying it, if it’s too high res for the display driver anyway. We’re just doing this before compiling the mobi/epub so that it should load quicker

  • Firstly I just want to say this is a truly great tutorial – thorough, clear and concise.
    Unfortunately when viewing my comic on E Book on an Android device it looks terrible. Pages are stretched, cut up, and totally out of order.

    Question – Does the page format have to be portrait?
    I’ve formatted all my pages to landscape so as to work better on screen (or so I though).

    • I don’t think that the pages HAVE to be portrait. I guess it all depends on which orientation fits the specific book. The stretching might be the app trying to show you the images in full screen. There might be a setting (maybe something under “zoom” or “stretch” if there are options like that) that can help with that.

      The pages out of order thing is a strange one. As long as the images within your cbz/cbr are in the correct order – and they HAVE to have consistent name formatting, otherwise they will be displayed out of order – then any book app should read them in the correct order.

      It might be that trying your image in portrait and simply rotating your screen around might help with you android app.

  • ROCKGOD 1

    theres a border around the images in the epub