Optimizing images for use in Kindle

[davebaxter]

Originally Posted by sirbruce

Actually, I never knew .zip files would work. The way I do it is just create a dirctory under the pictures directory, and the image files in that new directory. The "book" will be named whatever the directory is named.

Well that's good to know, too! Kind of like how you create custom screensavers. Should have thought of that.... --Dave B.

[EaglePt]

For my Kindle2 (probably the DX) you make point the cursor at the image and then click to zoom in on the image which is then displayed optimally, according to its aspect ratio, as either in portrait mode (up to 600x800) or landscape mode (up to 800x600).

Color is not discarded viewed on the iPad, etc.

With Photoshop I adjusted all my images for best tonal range and added a 1px black border.

Peter

[Snakey]

I'm making images for my Kindle 3 and when I dumb down the palette to 16 colors I'm wondering whether it's smarter to use Perceptual or Adaptive methods. Adaptive gives significantly better results on the PC but it seems to make more sense that Perceptual would more accurately provide 16 colors that Kindle would then interpret into it's own 16 capable shades. Like if I use Adaptive and come out with 2 colors very close to black I'm assuming Kindle will map both of those to it's single blackest shade. Anyone got input on this? I tried comparing the two methods on my Kindle but it's hard to tell.

[aproudlove]

Hi,
While playing around with this I worked out the following method, I'm using photoshop but perhaps someone who uses a different application can adapt it for that?

Part 1 - Image size
So as I'm going to create a screensaver image, I resize my image to 800x600 and set the DPI to 72.
NB If you want to create an image for in-book use, use 640x525 and 72 DPI.

1) Image -> Image size
2) Height 800
3) Resolution 72

Part 2 - Convert to Grayscale (or Greyscale)
Next we need to convert it to a gray scale, there are numerous ways to do this depending on how fussy you are (i.e. how much data you want to preserve) but here are a couple of methods below.

Method 1

1) Image menu -> Mode - Grayscale
2) Select yes to discard the colour information
NB: With this method, you don't get to tweak the image before it's converted

Method 2

1) Image menu -> adjustments -> Channel mixer
2) Tick the monochrome box
3) Move the sliders around until your happy
4) Click OK
NB: This method allows you to tweak before conversion

Method 3

1) Image menu -> Adjustments -> Black and White
2) Move the sliders around until you're happy
3) Click OK
NB: Also allows adjustments to the image.

Method 4

1) Image menu - adjustments -> Desaturate
NB: No tweaking to image

Part 3 - Additional Tweaking
The following tweaks seemed to improve the image for me once it was displayed on the Kindle but YMMV, so really the best is to just try for yourself and see what suits you.

1) Select Menu - Select All
2) Filter Menu - Sharpen - Sharpen Edges
3) Image Menu - adjustments - Brightness/Contrast
4) Pump the contrast all the way up to 100% or what looks good to you

Part 4 - Saving
Now we need to make sure that its a 16 shade image

1) File - Save for Web and Devices (Older Photoshop versions should be save for web)
2) In the window that appears, set the following
i) Type to PNG-8
ii) Colours to 16
iii) Change Selective to Perceptual (or Greyscale)
iv) Change Dither type from Diffusion to Noise
v) Turn transparency off
3) Press Save (Not Done, done just returns you back into Photoshop)
4) Select where you want to save the file and press Save again.

Part 5 - Get the file on to your Kindle
NB: You need to have performed the Jailbreak and Screensaver hack to do this. Steps for this are available in the forum.

1) Connect your Kindle to the computer via USB
2) Once mounted open the Kindle "drive" and located the linkss folder, double-click it
3) Inside the linkss folder, you will see a screensavers folder, double-click it
4) Drag your image (or images) from where ever you saved it, into the open screensavers folder
5) Unmount/Eject your Kindle from the computer

Part 6 - View the Screensavers

1) Press Menu -> Settings
2) On the Settings screen press Menu - Restart
3) Your Kindle will restart, this may take around 30 seconds, don't panic just wait, eventually the Amazon Kindle startup screen will appear
4) Once booted you may have a blank screen or blank homepage, again just wait around 10 seconds or so, you're books and collections will re-appear.
5) Your new screensavers should now be visible when the device sleeps.

Hope this is useful for some of you. I don't claim that my method is the best but it works for me at least but if any of you have a better/faster method, please let us know or if you find a way to improve mine.

Cheers,

Andrew

aproudlove.squarespace.com

[DaleDe]

I find that pictures in Color convert to grayscale just fine on the device. This allows the eBook to work on other devices that may be in color. However if you wish to convert to monochrome then you can do 256 level gray in JPG which is generally a smaller file that PNG even when it is reduced to 16 colors.

[Snakey]

I tried letting the Kindle do the conversion from RGB (desaturated) to 16 shades and it looked far worse compared to cutting it down to 16 in Photoshop. I also find that pattern dither looks better than noise or diffusion most of the time. I've never had a situation where I thought noise was better than either of the other two. I do pretty much everything the way you've described aproudlove, your detailed instructions should be a help to lots of people. Nice job.