Displaying images on e-ink screens

Ea · 06-24-2008, 03:53 AM

I think this is the "most right" forum for this topic...
I would like to know more about how well e-ink screens displays images, and how much software and file formats matters.

I got into a discussion yesterday about displaying images on an e-ink devices - more specifically images and graphics that accompany fiction - for instance a map in a fantasy novel. It was suggested that e-ink displays (on a Kindle) are really poor for this, and one shouldn't bother. I agree that details may not show well, and that you really shouldn't bother too much with very small images; they have to be pretty close to full screen size. Also they have to be formatted with an e-ink display in mind; size-wise and quality-wise. But if they are, then I do think it's worth bothering.

My device is a Cybook Gen3 and I wondered if there might be differences in how well it displays images vs. a Kindle? (why the person I discussed it with were less positive about images on e-ink displays).

As RickyMaveety mentions here:

Quote:

... I haven't found that the Kindle dithers very well, but then maybe I need to experiment more.

Since the Kindle and the Cybook has similar screens I wondered if there could be differences regarding the software? How does the mobipockets format handle images? Like jpg's in an html file?

igorsk · 06-24-2008, 07:14 AM

The dithering has to be done in software, since the controller only accepts data in its native bit depts (2,3 or 4 bits). Different devices use different algorithms.

wallcraft · 06-24-2008, 10:52 AM

Quote:

Originally Posted by _Ea_

How does the mobipockets format handle images? Like jpg's in an html file?

MobiPocket originally only supported GIFs, and converted everything to GIF. They also tended to have small images, partially because of a small screen customer base and partially from a ~62KB image size limit. They now support, and favor, JPEG. Usually of any size, although some old devices may still need the images to be less than 62KB.

I can see advantages to customizing images for the target device, but in many cases I think the best approach is now to use as large a good quality image as possible e.g. 1024x1024 JPEGs. If it is in color, leave it in color. I do see advantages in "optimizing" the colors for 4-16 grey scales, if that can be done without relying on the details of how the device downscales. Screen resolutions will get higher, and screens may get a bit bigger. LCD 7" screens started out as 480x800, but now 600x1024 is common. A 9.7" E-Ink screen will be 825x1200. Also, some screens will be in landscape and others in portrait orientation.

RickyMaveety · 06-24-2008, 11:06 AM

Ea,

Keep in mind the context of the statement I made. The Kindle, left to its own devices, does not dither very well. All that means is that, if you just stick a color photo or a 256 shades of gray photo on a Kindle, with no other adjustments, it has been my experience that they do not display very well.

It is very easy to take a map, or a photo, or line art, and make it display very well on a Kindle. Right now, I would say it takes me about 30 seconds (more or less) to take a color image and prepare it for Kindle display.

So, even with a book with 30 illustrations, that's only 15 minutes, and I think the time is well spent.

I first noticed the problem (or what I see as a problem) when viewing one of the Beatrix Potter books. I noticed that some of the illustrations were sharp and crisp ... and some were very faded and hard to see.

When I looked at the same book on my PC, the reason became clear, the crisp images were black and white line art, the faded ones were color, and most of the colors had the same contrast value, such that they were all merged into the same shade of gray on the Kindle.

However, what wallcraft says is correct, if you are planning a book based on it displaying best with future technology, then by all means, leave the images large and in color. They will take up more room on the ebook, and the images will not display as well with the current technology, but you can't have everything.

Me .... I'd probably do an edition optimized for e-ink screens and one for color screens and let the consumer decide which they want. I don't happen to care all that much for color maps in my literature (unless the color adds some information). As I recall, all of the maps in my Lord of the Rings paperbacks were black and white line art, and they suited me just fine.

Ea · 06-25-2008, 10:18 AM

Thanks for the inputs, all!

I also find it worthwhile to consider formatting images with an e-ink screen in mind, and pictures don't have to be in colour to look nice and illustrate the text. I guess for most e-books, any images are not specially formatted at all - just look like on paper - or formatted for an ordinary computer screen, not small handheld displays.

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06-24-2008, 07:14 AM	#2
igorsk Wizard Posts: 3,442 Karma: 300001 Join Date: Sep 2006 Location: Belgium Device: PRS-500/505/700, Kindle, Cybook Gen3, Words Gear	The dithering has to be done in software, since the controller only accepts data in its native bit depts (2,3 or 4 bits). Different devices use different algorithms.

06-24-2008, 11:06 AM	#4
RickyMaveety Holy S**T!!! Posts: 5,213 Karma: 108401 Join Date: Jun 2008 Location: San Diego, California!! Device: Kindle and iPad	Ea, Keep in mind the context of the statement I made. The Kindle, left to its own devices, does not dither very well. All that means is that, if you just stick a color photo or a 256 shades of gray photo on a Kindle, with no other adjustments, it has been my experience that they do not display very well. It is very easy to take a map, or a photo, or line art, and make it display very well on a Kindle. Right now, I would say it takes me about 30 seconds (more or less) to take a color image and prepare it for Kindle display. So, even with a book with 30 illustrations, that's only 15 minutes, and I think the time is well spent. I first noticed the problem (or what I see as a problem) when viewing one of the Beatrix Potter books. I noticed that some of the illustrations were sharp and crisp ... and some were very faded and hard to see. When I looked at the same book on my PC, the reason became clear, the crisp images were black and white line art, the faded ones were color, and most of the colors had the same contrast value, such that they were all merged into the same shade of gray on the Kindle. However, what wallcraft says is correct, if you are planning a book based on it displaying best with future technology, then by all means, leave the images large and in color. They will take up more room on the ebook, and the images will not display as well with the current technology, but you can't have everything. Me .... I'd probably do an edition optimized for e-ink screens and one for color screens and let the consumer decide which they want. I don't happen to care all that much for color maps in my literature (unless the color adds some information). As I recall, all of the maps in my Lord of the Rings paperbacks were black and white line art, and they suited me just fine.

06-25-2008, 10:18 AM	#5
Ea Wizard Posts: 3,490 Karma: 5239563 Join Date: Jan 2008 Location: Denmark Device: Kindle 3\|iPad air\|iPhone 4S	Thanks for the inputs, all! I also find it worthwhile to consider formatting images with an e-ink screen in mind, and pictures don't have to be in colour to look nice and illustrate the text. I guess for most e-books, any images are not specially formatted at all - just look like on paper - or formatted for an ordinary computer screen, not small handheld displays.

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