epub conversion adding extra blank pages to ends of chapters

[Guest]

I can't figure out why this is happening. Another user posted about it in 2016, and the post was moved to the "epub forum" and was never answered. I have known of the (theoretical) existance of this forum, but seems like something changed on the website and we can't actually search for anything in that "forum" or post anything directly to it—even if we add the epub subject tag. But trying anyway.

The file is currently built in CC2018 and I have not really run into this before. The chapters are in a Book file. There is no overset text, nor extra returns or page breaks at the ends of the file. All text and objects are in a single thread in the documents.

When previewing the epub in iBooks there seems to be anywhere for 5 to 16 or so added blanks. looking at the HTML in the unzipped files these are divs with a uniquely numbered image container and a class, within a Basic Text Fram class. Like so:

<div class="_idGenObjectLayout-3">
<div id="_idContainer287" class="Basic-Text-Frame">
</div>
</div>
<div class="_idGenObjectLayout-3">
<div id="_idContainer288" class="Basic-Text-Frame">
</div>
</div>

I don't have any blank boxes in the files that I can find. 

Has anyone else figured out why the extra pages and how to avoid that?

I can removed them in the HTML code, but I would surely prefer not to have to. There ARE background colred pages in the document on other hidden layers (used in the print version) but these shoudn't be exporting at all. Seem's like it would be many more pages ifo that were the case.

Two perhaps related questions: 

1. What is the corrct choice for exporting a book with images to include "classes" or not to include. The default is to include and I've always done that. 

2. Why does an epub exported from a book file with multiple separate ID chapter files create another CSS for each chapter? These are mostly full of idGenObjectAttributes, but why couldn't those be all in one CSS? I believe they are needed for calling out the sizes of objects when they are are all different—I've selected Preserve Appearance and Relative to Text Flow for most images. This is a complex reflowable ebook and writing a single CSS myself would be impossible for me. But all these CSS docs are pretty unwieldly.

[HSBurton]

Well, I don't think that would work well for me, because I've naturally
split the epub using header paragraph styles that I've used in my NAV TOC
and in-book TOC, so in order to do things that way it seems to me that I'd
have to add a "dummy paragraph style" right before all of those, which
seems far more trouble than it's worth to me, particularly given that, as I
said, the script I'm using seems to do what I need perfectly well with a
couple of clicks.

More generally, however, I am certainly not claiming that I have found *the*
solution or even the best solution, merely one that seems to work well for
me and thought there might be others out there who might be having the same
difficulties and appreciate it as well. Å chacun son goût.

Regards,

Howard

[Fab Dog]

My extra blank pages issue is not being caused by hidden frames, but by my images. I can't figure out the right combination of image size, image settings, and object export setting. Even small images tend to add extra space at the end (on Apple Books only by the way). Could the issue be with the image's actual size, not it's display box?

[Guest]

My extra blank pages issue is not being caused by hidden frames, but by my images. I can't figure out the right combination of image size, image settings, and object export setting. Even small images tend to add extra space at the end (on Apple Books only by the way). Could the issue be with the image's actual size, not it's display box?

By @Fab Dog

I don't know how that's happening. It's pretty tough to diagnose without seeing the code it is spitting out. 

Are your images in line, in the flow of text?

As for settings and sizes, it's taken me a long time to figure this out. You don't want to select "Use Existing Image for Graphic Objects" on export if your images are very large, as that will make your file size too big. Play around with the Object export settings for each image as this will produce slightly different results in the EPUB. But again, I don't think that's the issue with the extra pages. Yes, I think it was mainly an iBooks issue, but you can't really test it in every type of ereader, so it's good to fix it.

Can you unzip the epub and look at what's happening in an html editor, like dreamweaver, or BBEdit? (or even in Text Edit) That would at least show you if there are extra divs at the bottoms of your chapters, and it may tell you what they are.

[Fab_Dog]

Hi, Sue! Thank you so much for your help!

My images are anchored ABOVE LINE, and I am not selecting the "Use Existing Image for Graphic Objects".

When you say play around with the Object export setting, can you elaborate?

I'm not that great with HTML, but I will look into your suggestion!

Thanks again!

[Sarayu]

I'm having a different problem, which i haven't seen here yet. I am getting a blnk page one time -- between the introduction and Chapter 1. I have tried every kind of workaround that i can think of, and have isolated the problem to the paragraph style for the first element of the new chapter -- the chapter number. When i remove the chapter number for chapter 1, then there is no blank page. But if i create a new paragraph style based on the original, i have the same problem. And every other chapter is fine. I think the problem is with the keep options, but have tried every variation, to no effect. And yes, i ran the text frame script, but that doesn't help. Anyone have any thoughts? Am out of ideas. 

[James Gifford—NitroPress]

Funny, I am, right this moment, working on some deep technical details of exactly this subject (page breaks and subsequent page-top spacing)!

What is the last paragraph before the new chapter page? Does it have any odd settings, or a significant amount of space below?

Do you have Split EPUB defined for the Chapter heading style?

Oh, and — what EPUB viewer are you using?

[Sarayu]

Thank you very much, James! I really appreciate your help. Here are the
answers to your questions. I was wondering.since it's only one blank page, I
could probably just erase the html code for that one page in Calibre, though
I don't know code well enough to know what to cut and what not. Here are the
questions:

What is the last paragraph before the new chapter page? Does it have any odd
settings, or a significant amount of space below?

It doesn't have any unusual settings, though it does have a lot of space
after the last lines (most of a page). But I tried cutting out the last few
paragraphs just to see if that was the problem, and I still got a blank
page.

Do you have Split EPUB defined for the Chapter heading style?

Yes, I do have split epub checked in the chapter no. style.

[James Gifford—NitroPress]

No, you shouldn't have to edit the EPUB and, while it was once a thing, it's a poor practice now.

Check that last paragraph and make sure it has no space-below defined, even as an override. (Look closely at everything on those two pages for any kind of formatting override.) Double-check both text frames to make sure no space or other wonky settings have been added.

And remember that if you 'Split EPUB,' you have to either specify the split paragraph style, or tell it to use the paragraphs defined for splitting. (If you're not aware of it, the hamburger menu on Paragraph Styles has an option to review and set all export settings in one list... check that for any anomalies as well.)

This is a simple problem. We just have to find that simple answer. 🙂

[Sarayu]

Thank you, James, i really appreciate your help. But do you think it's significant that when i removed the last paragraphs on the preceding page, nothing changed; but when i removed the chapter number, then the problem didn't occur. So it seems (to my uneducated eye) that the paragraph style on "Chapter One" is the problem, but curiously the same paragraph style was used for all other chapters without a problem? Anyway, i will go through it as you suggested, as that sounds like really good advice.

[James Gifford—NitroPress]

It's hard to be precise about things from exchanging descriptions — I'd have to see the file to be sure. It could be a genuine bug of some kind, or just some detail that's being overlooked in my questions and your descriptions. I can't think of anything that would cause the blank page except Keep/break options, and space/padding where it doesn't belong. If the chapter number isn't causing an extra break anywhere else... that's really odd.

Try creating an alternate chapter number style (just for #1) that does not have break before defined (Keep: Next Page or the equivalent), and don't set that paragraph style to split the EPUB.

[Ruben Solér]

I just encountered a similar problem, but I also found the source of it. I got a blank page between all chapters in my EPUB3, but only in iBooks (the only other reader I tested with was Thorium to be fair).

I had used margin-top:20vh; to "push" my chapter headings down on the page. This worked perfectly in Thorium, but had no effect in iBooks, except adding a blank page before each chapter title. I got the same result with 10vh, 5vh, 2em, 10px, 20px etc: In iBooks the chapter heading stays at the top, but I get a blank page preceding it.

[James Gifford—NitroPress]

There basically is no vertical proportional spacing in EPUB, as there is only one "page" on which to base it and viewers vary in how they handle the arbitrary height of a virtual reader page. Almost any attempt to insert space using the relative methods (%, vh, etc.) will fail, and not always in a graceful way.

The only consistent way to have page-top spacing in reflowable EPUB across the readers and platforms is to use file splitting plus a page break plus hard space above the element. You can juggle and use only some of these factors and have it work in some readers, but to have it be a universal "start chapter heading spaced down the page" effect, you have to use them all.

A good example, though of how iBooks is almost a good, basic EPUB reader... except for a list of "better ideas" or "smarter behavior" that too many reader developers can't resist including. 🙂

[Ruben Solér]

All my chapters were split with a page break, but no hard space (I'll try that next time!). I managed to achieve the desired result with padding-top:20vh, although I guess this might not work on some other viewers.

[James Gifford—NitroPress]

Vertical spacing at virtual page tops is wholly at the discretion of the reader implementation, and as you've discovered, using the proportional units don't work on some great majority of them.

The only way to get consistent "chapter heading" top spacing and the like on a majority of readers is as I noted:

• Rule-above spacing to provide the effect in InDesign, with space-above also defined for export (verify and/or add in CSS);
• Page break before in InDesign (verified and/or added in CSS);
• Split document at export time, based on 'chapter head' style or equivalents.

Any other combination is likely to fail or be selectively implemented in the readers. There is redundancy here; while rule-above spacing is the only method that works in the InDesign layout, and space-above is ignored, it's the other way around in EPUB: the rule above is nulled out, while the space above defines the spacing as long as it has a hard page break to "push against."

The page break is also mostly for InDesign but adds to reliable interpretation at the reader level.

And most readers allow page-top spacing only at the start of a new document... which is why you need to split each chapter (etc.) into a new internal XHTML doc to assure the effect.

That one step or stage or reader or another might ignore a setting doesn't mean you can omit it from the whole process. 🙂