UPDATE: We’ve updated the info below to better reflect the current Amazon/Kindle marketplace.
LAST UPDATED 10/26/09
Time for a handy-dandy tutorial on adapting comics for the Kindle!
The Lowdown
Anyone can sign up to publish books on the Kindle. Just register an account at Amazon’s Digital Text Platform site, and then you’re ready to begin uploading your finished Kindle-adapted product!
Er…whoops, how does someone adapt a comic for the Kindle? Just resize some pages and submit?
Wouldn’t that be nice. No, alas, there’s lots to know, and a plethora of misinformation bread-crumbed across the internet to confuse the issue as much as it possibly could be. But here’s the full skinny as it currently stands with optimizing for the Kindle 2 device, and we’ll additionally touch upon the possibilities of adapting for the DX and First Generation devices as we go.
Zip file with HTML
The final file for uploading to Amazon should be a ZIP file, containing all the images/pages of the comic, alongside an HTML document included inside the zip, informing Amazon the order and style in which the contents will be displayed.
We’ll go over the HTML in detail in part 2 of this tutorial series, but for now, let’s focus on optimizing the images.
Size and centering
The screen resolution of the Kindle 2 is 600px x 800px, but this is not the actual display area when a book is reformatted and purchased via the official Amazon marketplace. You can upload a comic directly from your computer and still have it display “Full Screen”, but if you sell through Amazon, your final page display area is, maximum, 525px 640px.
If you make the image smaller than this, it’ll be automatically resized to fill in the remaining area, and the enlargement will cause the quality of the image to suffer. If you make it too big, it’ll be downsized and what you thought was legible and large enough to read likely won’t be anymore. The good news is that only ONE side needs to be at the maximum, because Amazon won’t change your images’ width/height ratio. So for example, if an image is 500 x 600, Amazon will auto resize it to 525 x 630 – the full width but not the full height, because only one side needs to reach the maximum. Keeping the ratio the same between the original width and height, the image reaches 525 in width when the height is only 630. Ergo: 525 x 630.
On the other hand, if your image is 450 x 640, or say 525 x 525, the image will not be resized at all, because one side is already at the maximum.
For any comics you release unofficially through venues other than the Amazon marketplace, the full size of the Kindle screen and therefore your images can be as big as 600px x 800px.
Due to this, most comic pages need to be broken down into smaller than page-sized screenshots.
And lest you think the Kindle DX will be the great saving grace on this point, currently, Amazon has no software in place to determine if a book is being downloaded for a Kindle 1, 2, or DX, and so all images are automatically resized to fit the device – upsized for the DX, downsized for the K2. There is no one-size-fits-all, although you do have the option to publish the book twice, one completely different adaptation for each Kindle model. Seeing as how most Kindle users are still K2 users, so much for that idea, eh?
One final but important note: you cannot center images with HTML on the Kindle (you can horizontally but not vertically). To work around this, and make absolutely certain your image is never resized after it’s optimized, cut and paste your final screenshot into the center of a 525 x 640 background. Voila! Now your images are all the fullest size possible, and always centered perfectly.
So instead of this:
Create this (Black background added for obvious separation between original image and the newly added space):
Optimizing the Image Quality on the Kindle 2
Size isn’t everything, and you’ll need to follow these very important guidelines to get the best resolution possible on the Kindle 2 16-shade screen. Make sure you’re using as high quality an original image as possible, and then:
- RESIZE the image first! Do not do any of the below until you’ve completed that very important step. If you resize later you’ll be left with some very ugly images indeed. Resize to 72-96dpi (300dpi is unnecessary when speaking of digital, and makes overly-large file-sizes, which the Kindle doesn’t handle so well)
- CROP ALL EXTRANEOUS MARGINS. You’re already downsizing to fit a small-ish screen. Why let any precious space be taken up by white or black margins?
- SHARPEN your image. If you’re using Photoshop, the best thing to do is use the Filter “Sharpen Edges”. If the text is hand-drawn or overly tiny (unable to by resized), then also use plain ol’ vanilla “Sharpen” to boot. The image will look overly crisp on your computer monitor, but it’ll make a huge difference on the fuzzier Kindle screen. UPDATE: This will depend entirely on the original art itself. Some art will not require this sharpening and indeed look pixelated and horrible with it, and some will depend entirely upon it, appearing as if behind a veil of digital fog without it. Fun, eh? We highly, highly recommend that you find someone with a Kindle to test your art for you before you publish. It’s necessary.
- INCREASE THE CONTRAST TO 100% – or if not 100%, increase it to where the white and black (or dark and light) areas are extra separated from each other. Since the Kindle is actually shades of GRAY and not at all black-and-white, it needs whatever help in can get to help divvy up the shades and keep your picture sharp and crystal clear.
- BRIGHTEN OR DARKEN the image. Depending on the original art, and what occurs when the Contrast is increased, it will likely be best to increase the Brightness or decrease it. If the image is overly dark, brighten. If it’s overly white/bright, darken.
- Save as a PNG-8, 16 Colors, “Perceptual” color reduction algorithm, and “Noise” Dithering. PNG-8 because anything more is lost on the Kindle’s 16-shade only screen, and would simply create an overly large file with zero gained result. 16 Colors to match the 16 shades of Kindle 2 e-Ink. “Perceptual” and “Noise” because they toss in additional very small specks of shade that help fool the Kindle into believing there are more shades of gray than there actually are.
And that’s it! You’ve got a perfectly adapted-for-the-Kindle comic image!
Please note that the image maylook terrible on your PC or Mac. The level of Sharpness, the low-quality PNG-8 with extra contrast, Noise, etc., etc., will all combine to make a god-awful looking thing starting back at you. But after it goes through the Amazon process and gets spat back out as an azw, you’ll see the final result for yourself.
Here’s a sample of an image screenshot not optimized:
And here it is optimized:
Pretty damn ugly, eh? Or, at least it’s quite different than what one expects an “optimized” page of art to look like. Again, however, if your art is already large, thick-lined, and light on the detail, this may be unnecessary.
If you don’t have a Kindle to test the final product, you can publish, wait for the book to go up, purchase a copy, and have Amazon send the azw file to your computer. Then use a free online program such as Mobipocket eReader to check it out.
Next in part 2: the HTML document (Now up! CLICK HERE).
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August 12th, 2009 at 7:54 am
[...] You can read PART 1: OPTIMIZING THE IMAGES by CLICKING HERE. [...]