base font size ? What unit should I use ?

[NASCARaddicted]

by the way, just to keep you updated, here are some things that I noticed - and basically solve my problem.

Some time ago, I downloaded a german epub ebook (Robinson Crusoe) from MR. I started to read it, but due to lack of time I didn't come far. Also, there have been other ebooks that I also wanted to read prior to this ebook.

Recently, I continued on this ebook. The font size on it was really good (I just checked and I get between 58-68 characters per line), so I unpacked the epub and looked at the css and the html files for something related to base size. And to my surprise, I didn't find anything ...

Well, before I continue, I have to start at the beginning: As I mentioned, standard epubs (that means without any change in fontsize) on the Bebook are awfully small. So when I convert from html to epub with calibre, I told calibre to change the font size to something around 20-24 pt. Since I was new into ebook readers I also tried the zoom button, but I noticed that only the first 2-3 zoom levels are useful, the other zoom levels were like: 2 lines per page (meaning 3 characters per line, not even a full word) - so deep did the Bebook zoom in.
So the whole zoom stuff was useless, since reading like 2 lines per page is rubbish.

Back to Robinson Crusoe. Out of boredom, I tried the zoom button and to my surprise, the zoom levels there were totally different. Even at the highest zoom level, the zoom was still useful (for half blind people, I have to admit). And the biggest surprise was yet to come.

I guess the zoom button is similar on many ebook readers. At least this is how it is on the Bebook: It goes only in 1 direction. So you zoom in and in and in, and once you are at the maximum zoom, the next level is back to the smallest again. And guess what: the smallest zoom level (or so to say: no zoom at all) is awfully small. Zooming in once got me back to the point, where the ideal 66 characters per line ...

So, when I use Zoom 1, the epub looks perfect, with the standard font size. But without zoom, the epubs are too small on the Bebook ...

So from now on, I will do my epubs without a base fontsize and just zoom in once ...

[quillaja]

Please, please, don't specify a font size for normal text unless there's a good reason. If you really want to, use em. If you use pt, mm, px, then it could possibly be fixed at that size depending on how the reading system zooms/alters text size. It's just bad, particularly if you'll ever give the book to someone else.

Case in point: I recently bought China Mieville's "Iron Council" from the sony ebook store. The publisher apparently thought setting the font size to "impossibly tiny" was a good idea. I had to set my prs-600 to L just to bring the font size back to normal. It was completely stupid (especially in addition to the general poor quality of ebook. (Mieville's story, however, was amazing.))

[JSWolf]

What I've found happens a lot is that the CSS is set to use small or even worse sometimes x-small. So I go into the CSS and remove font sizes for the main text except where is should be a different size. So basically, most books will have the body size at the default size which is then good for sizing up if you need/want to.

But, in order to do this on DRMed ePub, I first have to strip the DRM. I edit all my ePub I buy so they look more like a book should look instead on something generated by a poorly written computer program.

As for margins, don't use em as that will change the margins when the font size is changed. The margins are supposed to be fixed. The only place I use an em is text-indent as I use 1.1em.