Optimizing images for use in Kindle - Page 2

kineticone · 06-06-2008, 03:45 PM

the information regarding the kindle display comes directly from the amazon DTP website and kindle forum administrators.

in my experience, having a computer/device resize an image to fit the viewing area results in reduced image quality, additional processing time and larger than necessary file sizes. (see any large image resized in any IE browser window) if you are going to take the time to size your images, why not size them correctly in the first place instead of forcing them to fit?

it is true that kindle resizes to a certain aspect ratio so using larger graphics will work if image quality is less of a priority than getting the book "published". not every resized image will look bad, but why chance it? (my opinion)

the 520x620 dimensions mentioned above have about the same aspect ratio of the DTP posted limitations of 450x550. the slight delay that the users notice may be the kindle resizing the image to 450x550.

i have no first-hand experience with using larger than 64kb images as grayscale images are very small to begin with and there's no reason to include extra color data that will be lost and muddied by the reader device, i think. in any case, that is the official guideline posted by amazon.

wallcraft · 06-06-2008, 04:16 PM

Quote:

Originally Posted by kineticone

if you are going to take the time to size your images, why not size them correctly in the first place instead of forcing them to fit?

I agree, but the right size is 520x640 not 450x550. If you look at my screenshots from the Kindle, all the larger images have been resized (by the Kindle) to be 640 pixels high so 550 pixels high definitely isn't the maximum allowed.

HarryT · 06-07-2008, 06:04 AM

Quote:

Originally Posted by kineticone

if you are going to take the time to size your images, why not size them correctly in the first place instead of forcing them to fit?

One very good reason is that what is "correct" for the Kindle is not optimal for other devices and, if one is producing a "generic" MobiPocket book, the Kindle may not be one's only "target".

For example, for my own main MobiPocket device - the CyBook Gen3 - images with heights of around 760 pixels are "optimal".

RickyMaveety · 06-07-2008, 12:33 PM

All of this is very interesting. I would have thought an 800 x600 screen would mean 800 x 600 images.

So, if I'm thinking bookplates for the Kindle, then they should properly be 550 x 450??

As for creating 4 shade gray scale images, I've done it with PS, but my favorite tool is really an old version (8.1) of Paint Shop Pro. You can save various four color palattes and load them sequentially to see which one is best for your particular image.

RickyMaveety · 06-07-2008, 12:49 PM

This is a comparison of an image I drew for a book that I've been working on (forever ... really ... forever). The four shade grayscale was created in PSP using their "X colors" command after first putting the image in grayscale.

I tend to leave anything with that small of a palette in gif format. I'm not certain that having it be a jpg (which is more lossy) adds much to the equasion, but I could certainly look into that.

wallcraft · 06-07-2008, 12:55 PM

Quote:

Originally Posted by RickyMaveety

All of this is very interesting. I would have thought an 800 x600 screen would mean 800 x 600 images.

So, if I'm thinking bookplates for the Kindle, then they should properly be 550 x 450??

There is a difference between screensaver images, which fill the 600x800 screen, and images in a MOBI/AZW ebook which are limited to 520x640. Also the latter will be resized for you if they are too big, but the screensaver images need to be exactly the right size and format. See Kindle Screensaver.

RickyMaveety · 06-07-2008, 12:59 PM

Got it .... so when I'm creating bookplate screensavers for the Kindle, those can be 600 x 800, but I should make the images in the book, the smaller size (depending on what size would be the best for the various types of e books.

Not that my book is going to hit the market anytime real soon. It's taking me ever so long to draw each image, and even longer to get the inspiration for each one.

kineticone · 06-08-2008, 02:42 PM

Hey Ricky-

As you can see from these posts, nearly every digital reader device has different settings for the images they can display. As I work with my artists and they begin to get mired in the tech of the end product, I always remind them to create their art at the size and in the medium they are most comfortable with. We can "fix it in post" as it were for almost anything.

Don't get discouraged by all this tech talk when your work is hard enough just coming up with the ideas and putting your craft together! When all of the words and images/paintings/photos are together then decide on the platform(s) you will publish on and size/resize from there. By the time you finish one project many technologies will have changed and most of these posts will be moot anyway.

exfish · 09-15-2008, 01:16 PM

I ran an experiment to get to the bottom of all this. I'm doing thesis research on type design for e-paper, so actual dimensions and pixel sizes are important to me. You can read about my results here. Looks to me like 520 by 640 is the "native" reslution, and anything else gets resized.

wallcraft · 09-15-2008, 01:24 PM

Quote:

Originally Posted by exfish

Looks to me like 520 by 640 is the "native" reslution, and anything else gets resized.

I originally thought 520x640, but I now think 525x640 is the correct maximum size. See Kindle Automatically Doubles Image Sizes. Note that 520x640 won't get resized because its height is at the maximum. The difference between 520 and 525 only comes into play when the width is what controls resizing.

exfish · 09-15-2008, 04:50 PM

Quote:

Originally Posted by wallcraft

Note that 520x640 won't get resized because its height is at the maximum. The difference between 520 and 525 only comes into play when the width is what controls resizing.

Huh, interesting. That gives me five more pixels of wiggle room for my type specimens! It ain't much, but every little bit helps.

ProDigit · 10-17-2008, 03:05 AM

Quote:

Originally Posted by wallcraft

Attached are the originals and the associated Kindle screenshots for 3 jpg images. The first is a cover image from FeedBooks, its original size is 595x842 (37KB) and it gets rescaled just like images in the interior of the ebook. The last two are from bob_ninja's version of Potter, Beatrix: The Tale of Samuel Whiskers. v1, 16 May 2008, one is 931x1264 (117KB) and the other, in color, is 603x736 (74KB). All three images are relatively tall but this confirms the 520x640 actual size, the rescaling (maintaining aspect ratio) and the support for jpg's > 64KB. There is a noticeable pause before displaying a page containing an image, but illustrated ebooks work well on the Kindle. It is a shame that some professionally produced ebooks have much smaller images than those shown here.

Wished I could see some more jpegs converted!
The color image has nice dirthering!

Daithi · 12-03-2008, 02:59 PM

I found a trick that might help others in creating a grayscale image in photoshop. In the tab that shows all of your layers click the tab next to it labeled Channels. Now you can click each Channel (Red, Green, and Blue) to see which one has the best contrast. Normally, I copy the image in the channel that looks best and then create a new image (this way I don't muck with my color image).

Alternatively, if you want even more control, you can select Layer/Adjustments/Channel Mixer and then check the monochrome button. Now you can play with the sliders to see which one(s) gives you the best contrast. I've also found Layer/Adjustments/Posterize helpful as well (with a setting of 16).

ONLY after using one of these techniques do I try adjusting contrast/brightness.

Then click Save for the Web and ALWAYS save it as a GIF file. Set your colors to 4 colors, No Transparency, and play with Adaptive/Perceptual/etc, and Pattern/Noise/etc.

One thing I haven't figured out yet is what the values of the four colors should be set to. It just occured to me that I should do a Alt-Shift-D to save a screen image then edit that with photoshop to see what values the Kindle is using, but I haven't done that yet.

Daithi · 12-03-2008, 06:03 PM

This is the first time I've tried entering a picture on the forum, so hopefully this won't look like crap. If it does then you can look at a color image of one of my covers here

http://s415.photobucket.com/albums/p...MidSummer1.jpg

and a 4 color B&W here

http://s415.photobucket.com/albums/p...dSummer1-1.gif

Note: They definately look better at 100%.

Color JPG

4 color B&W GIF version

Daithi · 12-03-2008, 06:05 PM

Oh well, I tried. You'll have to click the links to see the images.

06-07-2008, 12:33 PM	#19
RickyMaveety Holy S**T!!! Posts: 5,213 Karma: 108401 Join Date: Jun 2008 Location: San Diego, California!! Device: Kindle and iPad	All of this is very interesting. I would have thought an 800 x600 screen would mean 800 x 600 images. So, if I'm thinking bookplates for the Kindle, then they should properly be 550 x 450?? As for creating 4 shade gray scale images, I've done it with PS, but my favorite tool is really an old version (8.1) of Paint Shop Pro. You can save various four color palattes and load them sequentially to see which one is best for your particular image. Last edited by RickyMaveety; 06-07-2008 at 12:34 PM. Reason: because I can't freaking type

09-15-2008, 01:16 PM	#24
exfish Junior Member Posts: 2 Karma: 10 Join Date: Sep 2008 Device: Kindle	Empirical evidence and testing I ran an experiment to get to the bottom of all this. I'm doing thesis research on type design for e-paper, so actual dimensions and pixel sizes are important to me. You can read about my results here. Looks to me like 520 by 640 is the "native" reslution, and anything else gets resized.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What's the dpi in Kindle images?	reamo	Amazon Kindle	3	05-28-2010 12:12 PM
Anyone have optimizing tips for PDF files?	stevet	PDF	4	03-05-2010 12:40 AM
viewing images on kindle	romnempire	Amazon Kindle	5	12-29-2009 12:09 AM
Displaying images on Kindle?	beagley@alma.edu	Amazon Kindle	2	12-28-2008 06:06 PM
Kindle Images	Adam B.	Amazon Kindle	14	01-12-2008 11:51 PM

06-06-2008, 03:45 PM	#16
kineticone Gimongous Member Posts: 3 Karma: 13 Join Date: Jun 2008 Location: Sacramento, California - Vieques Island, Puerto Rico Device: kindle	the information regarding the kindle display comes directly from the amazon DTP website and kindle forum administrators. in my experience, having a computer/device resize an image to fit the viewing area results in reduced image quality, additional processing time and larger than necessary file sizes. (see any large image resized in any IE browser window) if you are going to take the time to size your images, why not size them correctly in the first place instead of forcing them to fit? it is true that kindle resizes to a certain aspect ratio so using larger graphics will work if image quality is less of a priority than getting the book "published". not every resized image will look bad, but why chance it? (my opinion) the 520x620 dimensions mentioned above have about the same aspect ratio of the DTP posted limitations of 450x550. the slight delay that the users notice may be the kindle resizing the image to 450x550. i have no first-hand experience with using larger than 64kb images as grayscale images are very small to begin with and there's no reason to include extra color data that will be lost and muddied by the reader device, i think. in any case, that is the official guideline posted by amazon.

06-07-2008, 12:49 PM	#20
RickyMaveety Holy S**T!!! Posts: 5,213 Karma: 108401 Join Date: Jun 2008 Location: San Diego, California!! Device: Kindle and iPad	This is a comparison of an image I drew for a book that I've been working on (forever ... really ... forever). The four shade grayscale was created in PSP using their "X colors" command after first putting the image in grayscale. I tend to leave anything with that small of a palette in gif format. I'm not certain that having it be a jpg (which is more lossy) adds much to the equasion, but I could certainly look into that.

06-07-2008, 12:59 PM	#22
RickyMaveety Holy S**T!!! Posts: 5,213 Karma: 108401 Join Date: Jun 2008 Location: San Diego, California!! Device: Kindle and iPad	Got it .... so when I'm creating bookplate screensavers for the Kindle, those can be 600 x 800, but I should make the images in the book, the smaller size (depending on what size would be the best for the various types of e books. Not that my book is going to hit the market anytime real soon. It's taking me ever so long to draw each image, and even longer to get the inspiration for each one.

06-08-2008, 02:42 PM	#23
kineticone Gimongous Member Posts: 3 Karma: 13 Join Date: Jun 2008 Location: Sacramento, California - Vieques Island, Puerto Rico Device: kindle	Hey Ricky- As you can see from these posts, nearly every digital reader device has different settings for the images they can display. As I work with my artists and they begin to get mired in the tech of the end product, I always remind them to create their art at the size and in the medium they are most comfortable with. We can "fix it in post" as it were for almost anything. Don't get discouraged by all this tech talk when your work is hard enough just coming up with the ideas and putting your craft together! When all of the words and images/paintings/photos are together then decide on the platform(s) you will publish on and size/resize from there. By the time you finish one project many technologies will have changed and most of these posts will be moot anyway.

12-03-2008, 02:59 PM	#28
Daithi Publishers are evil! Posts: 2,418 Karma: 36205264 Join Date: Mar 2008 Location: Rhode Island Device: Various Kindles	I found a trick that might help others in creating a grayscale image in photoshop. In the tab that shows all of your layers click the tab next to it labeled Channels. Now you can click each Channel (Red, Green, and Blue) to see which one has the best contrast. Normally, I copy the image in the channel that looks best and then create a new image (this way I don't muck with my color image). Alternatively, if you want even more control, you can select Layer/Adjustments/Channel Mixer and then check the monochrome button. Now you can play with the sliders to see which one(s) gives you the best contrast. I've also found Layer/Adjustments/Posterize helpful as well (with a setting of 16). ONLY after using one of these techniques do I try adjusting contrast/brightness. Then click Save for the Web and ALWAYS save it as a GIF file. Set your colors to 4 colors, No Transparency, and play with Adaptive/Perceptual/etc, and Pattern/Noise/etc. One thing I haven't figured out yet is what the values of the four colors should be set to. It just occured to me that I should do a Alt-Shift-D to save a screen image then edit that with photoshop to see what values the Kindle is using, but I haven't done that yet.

12-03-2008, 06:03 PM	#29
Daithi Publishers are evil! Posts: 2,418 Karma: 36205264 Join Date: Mar 2008 Location: Rhode Island Device: Various Kindles	This is the first time I've tried entering a picture on the forum, so hopefully this won't look like crap. If it does then you can look at a color image of one of my covers here http://s415.photobucket.com/albums/p...MidSummer1.jpg and a 4 color B&W here http://s415.photobucket.com/albums/p...dSummer1-1.gif Note: They definately look better at 100%. Color JPG 4 color B&W GIF version

12-03-2008, 06:05 PM	#30
Daithi Publishers are evil! Posts: 2,418 Karma: 36205264 Join Date: Mar 2008 Location: Rhode Island Device: Various Kindles	Oh well, I tried. You'll have to click the links to see the images.

Advert

Advert