What is a good InDesign documet setup for an iPhone app/ebook?

[MikeT999]

I'm using InDesign5 to create an ebook that is optimized for displaying on the iPhone.

In particular, I'm looking for appropriate dimensions of the base page, in pixels, to enter in the Document Setup dialog box.

From what I've read, 320 x 480 pixels should work well for both the iPhone 4 as well as previous versions.

Is that accurate?

The Setup page also includes boxes for Bleed and Slug. Should any values be entered there, or should they remain zero?

Thanks for the help.

-- Mike

 

[spamjim]

I thought ebooks are optimized for display anywhere and do not require resolution settings.

480x320 is the resolution of iPhone/iPod touch prior to 2010.

Bleed and slug is for printing.

http://www.creativepro.com/files/downloads/InDesignMag_32_ebooks_part1.pdf

http://www.creativepro.com/files/downloads/InDesignMag_32_ebooks_part2.pdf

 

[MikeT999]

As I understand it, epub files (a common format for ebooks, but there are many others) are comprised mostly HTML files. Graphics in these files are bitmaps -- JPG, GIF, etc. InDesign and other epub "generators" automatically convert any vector-based files to bitmaps.

(The text in an epub file reflows when it is displayed, without regard for page breaks. Anchored images will reflow with the text. But without doing some fancy programming, image resolution stays constant.)

As I mentioned before, InDesign 5 gives four resolution options. I'm wondering which one is best for the iPhone 4 and its predecessors.

Apple says the iPhone4's display is 640x960, while predecessors are 320x480. I've read iOS4 processes images in such a way that using 320x480 is the best way to go for almost all apps/books.

I'm wondering which InDesign export option would be best.

-- Mike

 

[spamjim]

If you recognize that epub is XHTML and will scale/reflow to various sizes on various devices, why are you concerned about starting out with a document that is of any particular resolution or size?

 

[MikeT999]

>>>why are you concerned about starting out with a document that is of any particular resolution or size?

Size: Because I assumed -- at least somewhat incorrectly -- that optimizing the HxW of InDesign's base page would in turn optimize how the epub is displayed and, secondarily, how efficient it was.

I'm not ready to entirely give up on this assumption, based on the test files I've created so far.

Resolution: Basically, for the same reasons as above. I want smaller files that generate adequately crisp images when viewed on a particular device (the iPhone in this case). I didn't (don't) understand the effects of choosing between InDesign's export function and its low/med/hi/max options for images.

For grins, I just created four epub files from the same small test file, changing only the image setting in the JPEG box. I then unzipped the epub file and checked the properties of each of the four jpgs.

Anyway, all have the same HxWs in pixels (196x420), and all are 72 dpi. File size from low to max is 16, 18, 17, 43 Kb.

So, for this project, it looks like (literally!) that I'd gain nothing by opting for max.

-- Mike