View Full Version : Reference Guide: How to Prepare Images for EPUB (and other) Formats


Zorba
11-18-2009, 05:24 PM
Hello and thanks in advance,

I'm looking for some expert help on the subject of how to prepare images for ebooks, for the essential ebook formats, reading systems and devices. I thought that I could capture two pigeons with one bean if I not only gathered this information, but shared it with the epublishing community.

Please take a glance at this web page -- down on the bottom half of the page -- and you'll see the beginnings of some tables where much information is needed.

http://www.zorba.us/?page_id=676

The goal is to provide a quick and handy kind of "cheat sheet" for anyone making ebooks in some of the major formats: EPUB, PDF, Kindle.

Help with this project would be much appreciated, either by answers here, or contacting me directly. When this project is complete, or nearer to completion, I will post back to this thread.

Also, if someone at MobileRead would like to take charge of this project, and post this information on a MobileRead wiki page, I am happy to pass the torch.

Thanks again,

Michael Pastore
50 Benefits of Ebooks

Patricia
11-18-2009, 07:13 PM
Some of the information can be extracted from our wiki. For example, the image formats supported by each device are listed in the E-Book reader matrix:

http://wiki.mobileread.com/wiki/E-book_Reader_Matrix

JSWolf
11-18-2009, 07:29 PM
One bit of information is don't make the images any larger than 800x600 and make sure that they scale properly to fit the page.

Zorba
11-18-2009, 07:37 PM
Patricia, thank you. I'll visit that matrix and then add some image types.

JSWolf, thank you. Is that:

800 (width) by 600 (height),

or

800 (height) by 600 (width).

--MP

Patricia
11-19-2009, 12:01 AM
It is 800 pixels in height, and 600 in width.

Zorba
11-19-2009, 12:12 AM
Thanks again, Patricia.

I am writing to all the device makers, to get details -- about optimizing the images -- for viewing ebooks (in EPUB and PDF) on their devices.

I will report back here, to this thread, when some progress has been made.

-- MP

Rayven01
11-19-2009, 03:56 PM
One bit of information is don't make the images any larger than 800x600 and make sure that they scale properly to fit the page.

How do you make sure they scale properly, short of using vector graphics? Isn't that up to the device?

Zorba
11-19-2009, 10:48 PM
Hello Rayven01,

Until a graphics expert jumps in here, here is my guess.

I think that JSWof's good advice (which I will add to this project's web page) has something to do with the aspect ratio. I couldn't get an EPUB ebook cover image to show up using Stanza desktop, and then I adjusted the aspect ratio, making the image less wide, and then it appeared perfectly.

A test is always needed to see if the image shows up, if the image is still sharp, if it's in the right location, and so on.

--MP

pdurrant
11-20-2009, 04:53 AM
How do you make sure they scale properly, short of using vector graphics? Isn't that up to the device?

In ePub you can embed any image in an SVG wrapper, which can make it scale to fit the available space.

Jellby
11-20-2009, 10:11 AM
In ePub you can embed any image in an SVG wrapper, which can make it scale to fit the available space.

I'm not sure current renderers treat relative height specifications (e.g., 100%) as related to the screen size, though

hapax legomenon
11-20-2009, 05:03 PM
is it necessary to create a grayscale version of the image for e-ink devices?

Patricia
11-20-2009, 05:21 PM
is it necessary to create a grayscale version of the image for e-ink devices?

Not necesarily, hapax. I often leave my images in colour, just in case someone is reading on a PC or tablet. My Sony just shows greyscale in these cases.

Zorba
11-21-2009, 09:24 AM
Thanks, hapax, for the question, and thanks Patricia, for the reply.

This is one of the main points of my information-gathering project: to find "the right specs" so that ebook publishers can produce one -- only one ! -- version of the ebook that fit all the various reading systems (or: all the significant ones), and to avoid the trouble and chaos of needing to produce many different versions of the same ebook.

Michael Pastore
50 Benefits of Ebooks

hapax legomenon
11-22-2009, 09:28 AM
Here's another relevant document by keith fahlgren
http://blog.threepress.org/2009/11/20/best-practices-in-epub-cover-images/