iPad vs. Tablet vs. other output profiles

[PatNY]

I've been using the iPad output profile for both my iPod Touch and Sony reader and it works fine. But I noticed that it restricts the cover size to 1005 pixels on the long side. If you select a cover that is larger than that it will resize it down to 1005 pixels. But if you select a cover that is smaller than that there will be no resizing and the original image is kept. This is always my preference regardless of the size I use as successive resizing of jpegs can degrade image quality.

I would like to start to use even larger cover sizes -- such as 1200 pixels long -- and it seemed the tablet profile would suffice as the mouseover says no image resizing is done. But it got me wondering what are the differences between some profiles and does it really matter what I pick -- so long as it allows a desired cover size? So here are my specific questions:

1) Other than image and cover resizing, are there any significant differences between the iPad and Tablet profiles? Specifically any differences that might impact the readability of certain epubs on certain devices?

2) If I want to create epubs with large covers, what is the best profile to use for future-proofing those epubs and to ensure the best compatibility with the widest number of devices to make it easier to share epubs with family and friends?

3) Any downside to simply using the "Tablet" profile all the time? I did a test and it seems to work fine on my Touch and Sony reader. One day I might buy a tablet with a screen resolution higher than the iPad and so I would like some of my epub covers to fully fill the screen. Don't have such a tablet yet, though.

Again, future-proofing is one of my main considerations. Is it true that a new epub standard is being devised? If so, it won't impact the future compatibility of today's epubs, right?

[user_none]

Originally Posted by PatNY

1) Other than image and cover resizing, are there any significant differences between the iPad and Tablet profiles? Specifically any differences that might impact the readability of certain epubs on certain devices?

Image size is the biggest difference. The iPad profile also has some iPad specific CSS. However, this isn't helpful if you're not using iBooks. The CSS won't have a drastic impact.

Originally Posted by PatNY

2) If I want to create epubs with large covers, what is the best profile to use for future-proofing those epubs and to ensure the best compatibility with the widest number of devices to make it easier to share epubs with family and friends?

How large is too large? The calibre quick start guide started with a high quality very large cover but I had to replace it with a scaled down jpg because the cover alone accounted for two thirds of the file size. Either profile will keep the EPUB future proofed. The only major difference is the image size and even in the future are you going to need an image 10,000px by 10,000 px?

Originally Posted by PatNY

3) Any downside to simply using the "Tablet" profile all the time? I did a test and it seems to work fine on my Touch and Sony reader. One day I might buy a tablet with a screen resolution higher than the iPad and so I would like some of my epub covers to fully fill the screen. Don't have such a tablet yet, though.

The only downside is possibly larger file size.

Originally Posted by PatNY

Again, future-proofing is one of my main considerations. Is it true that a new epub standard is being devised? If so, it won't impact the future compatibility of today's epubs, right?

EPUB 3 was finalized not too long ago. Calibre I believe currently only outputs EPUB 2. EPUB 3 reading systems are required to be EPUB 2 compatible. Also, it is possible to create an EPUB 3 with fall back mechanisms so that file will read perfectly on an EPUB 2 reading system.