Aura H2O Font size mismatch (downloaded epubs via Calibre vs. Kobo epubs & articles)

[Oolong]

Most of my books are downloaded from other sources, and I use Calibre to get them onto the Kobo Aura H2O. I can't remember ever telling Calibre to do anything to the font size, but all the books that I get on there that way have fonts almost twice as big as those used for Pocket articles and Kobo epubs.

Does anyone/everyone else have this problem? Any tips on how to fix it? Kobo customer support brush me off with 'Given that these are third party titles, we are unable to fix these formatting differences.' But this is essentially all third party titles!

[patrik]

In my experience the epub-renderer defaults to a larger font than the kepub/pocket-renderer. Therefore if you go back and forth between them you will notice an annoying difference.

I wished the settings (that it remembers) was per renderer.

Back when I asked about this some years ago I think davidfor gave a tip that you could set the font-size to something below 1.0 in Calibre. That way everything that was transfered (as epub) to the Kobo got automatically adjusted to the same as the kepub/pocket-texts.

With a bit of luck David will pop-up here, or someone else who actually knows what they are talking about, in contrast to me.

[Oolong]

So this is a known bug, then?

[patrik]

Even if I find it annoying, it's no bug by any normal definition.

On one hand it is fantastic that you get the benefits of having two totally separate render-engines for the price of "one", on the other you get some things you have to handle manually, like this.

But, please contact Kobo and let them know that there are people who like to be able to save settings separately for the two render-engines (which would solve this, you set the size once for one of them, and you're done).

[ZodWallop]

If you have Calibre convert to kepub when it sends the books to the device, that would fix the problem, no? Then all your books would be using the same renderer.

[robko]

Originally Posted by patrik

... there are people who like to be able to save settings separately for the two render-engines (which would solve this, you set the size once for one of them, and you're done).

Not really. Different files (epubs anyway) can have radically different base font sizes so even if your reader remembers the size you set you may have a massively smaller or larger font on the next one you open. This has been discussed in past and it's hard to come up with a perfect solution that covers all possible circumstances on this.

[Oolong]

But if they're using two render engines which share settings, it makes *no* sense for the default font size for one to be radically different from the other.

[Oolong]

I get that base font sizes can vary radically from one epub to another, but it's this common? Mine all seem to be pretty consistent, and always much bigger than Kobo epubs. Is this an unusual experience?

[ScalyFreak]

Originally Posted by Oolong

But if they're using two render engines which share settings, it makes *no* sense for the default font size for one to be radically different from the other.

Sure it does. All that's required is for "Size X" to mean one thing for Render Engine A and a different thing for Render Engine B.

[Oolong]

Originally Posted by ScalyFreak

Sure it does. All that's required is for "Size X" to mean one thing for Render Engine A and a different thing for Render Engine B.

I didn't mean it doesn't make sense in terms of the inexorable GIGO logic of computers doing what someone told them to do, I meant it doesn't make any sense in terms of human-computer interaction. It's a bizarre user interface mistake.

[jackie_w]

It's interesting to note that with the KA1 this difference between font-size in epub and kepub no longer exists. I don't use Pocket on my Kobo so I can't comment about that.

I found this out the 'wrong way round'. On my H2O, GloHD I have been using a simple technique to equalise these perceived font-size differences, epub vs. kepub. So when I got the KA1 I just repeated the same process, only to find the kepub text was enormous. Once I removed the fix on the KA1 all was well again.

I'll outline the 'fix' here in case any H2O/GloHD owners are interested. No programming skills or Kobo patching required. There are some pre-requisites though:

1. Firstly, all your source books need to use the same standard basic font-size. Those who routinely massage their new books to do this will have no problem. For those who just read whatever the publisher gives them there is no solution.
2. Font-size styling inside your source books uses relative sizes (em, %) not absolute sizes (pt, px).
3. You're using calibre to transfer your kepubs to the Kobo.
4. Your books are DRM-free
5. You're able to follow the instructions in this thread

Once you've customised your calibre driver preferences (KoboTouch or KoboTouchExtended) and created your kobo_extra.css file from the last item just add the following line to the end of it and copy it to the root directory of your Kobo.

body>div#book-columns>div#book-inner {font-size:1.5em}

As you sideload your kepubs to the Kobo using calibre send-to-device the font scaling will be applied on-the-fly but the source book in your calibre library will remain unchanged. Standard epubs will just ignore this font scaling.

Note: 1.5em is the right scaling factor for me but try a different value if it's not right for you.

[JSWolf]

Originally Posted by Oolong

I get that base font sizes can vary radically from one epub to another, but it's this common? Mine all seem to be pretty consistent, and always much bigger than Kobo epubs. Is this an unusual experience?

Base font sizes in ePub can vary. I've seen some using small or some small font size less than 1em. Others don't specify a font size so you get the default. So yes, the base font size in an ePub can vary. But what I do is edit the ePub to take a look and if there is a base font size specified, I remove that and if any of the text in the ePub is made smaller such as offset text, I remove that too. I want the text to be a consistent size.

I'm not bothered with the size of chapter headings and stuff like that.

[Oolong]

ZodWallop's completely right:

Originally Posted by ZodWallop

If you have Calibre convert to kepub when it sends the books to the device, that would fix the problem

So far all the books I've converted look fine after converting them to kepub. Which, again... would not be a solution if the renderers were set up sensibly in the first place!

But since they're not, I'm quite happy with this solution.

Although... does anyone know an efficient way to remove all the old epub files? I've uploaded a load of converted files, but I didn't remove all the old files first, and it looks like this is prone to confusing the Kobo, though I could be wrong about that being why it kept losing my place...

[ZodWallop]

Originally Posted by Oolong

ZodWallop's completely right:

More threads should include this quote

Although... does anyone know an efficient way to remove all the old epub files? I've uploaded a load of converted files, but I didn't remove all the old files first, and it looks like this is prone to confusing the Kobo, though I could be wrong about that being why it kept losing my place...

I'm not at home right now, so I'm just going off of memory. But you should be able to plug the Kobo in and in Calibre, switch to the Kobo (or SD card if that's where your books are stored) instead of your library. Highlight all the books, right click and choose 'Remove files of a specific format from selected books' or 'Remove all Formats from selected books except'

If an ePub is the only format of the book on the Kobo, I believe it will leave it. It will only delete books that are on the Kobo in multiple formats.

[davidfor]

Originally Posted by Oolong

Although... does anyone know an efficient way to remove all the old epub files? I've uploaded a load of converted files, but I didn't remove all the old files first, and it looks like this is prone to confusing the Kobo, though I could be wrong about that being why it kept losing my place...

Can you explain how it is confusing your device? I have plenty of kepub and epub versions of the same book in my devices for testing purposes. And will put multiple copies of same format as well. At no point does it confuse the edvice. Confusing me, that's a different issue. I have to be careful I am opening the right version.

And ZodWallop right on how to clean it up. It's probably the easiest way. You can also do it form the library by searching for all books with multiple copies. But, the selective delete is a little harder. Or you could just delete all the books with multiple copies and send them again. You can also open the drive for the device when it is connected and delete the files there. When you disconnected, the device will remove the missing books from the database.