Digital manga and file sizes
Last week I mentioned that we use the native resolution of the iPad to avoid problems related to moiré effect and pixelation.
It’s still possible to see the pixels even in Amimaru, though. When you double-tap the screen to zoom and take a closer look at the details, the resolution of the 2048-pixel file can’t hold up. The zoomed-in Yami Kyun! picture in the middle up there is is an example in the native 2048 x 1536 resolution of the iPad screen.
The double-tap zooms in exactly 50%. So you might think that solving this problem would be easy – why not just double the resolution, to 4096 x 2880? This way the pages would look absolutely awesome, even when zoomed in. The zoomed-in picture on the left shows this option. Pretty sharp, can’t deny that.
(If you have a small screen, you might see some moiré in the images due to resizing. Try opening the links in tabs to see them full-sized.)
That would bring in a whole another set of problems, though – namely, the file size. At the moment, the files we use already have a file size of 1 to 1.5 megabytes per page. By doubling the resolution, the file size would climb to 4 megabytes or more, as you can see above.
Downloading files of this size would take at least twice as long, and the memory of your iPad would fill up two to five times as fast. We’re primarily a streaming service, so it isn’t really an option to make the files so large they takes tens of seconds to load. To make this worse the possible color pages are always the first ones, and those are even heavier than black-and-white pages.
We wrestled with this problem for a while. At one point we even considered offering two different resolutions – “SD”, or the current 2048 x 1536, and “HD”, the speculative 4096 x 2880. However, we ultimately decided against this, deciding that it would just add confusion and destroy the simplicity of the service. And the quality difference between the two options is not that huge to warrant the absurd increase in file size.
(By the way, the right-hand image up there is an example of how our manga would look if we offered it in non-retina resolution – 1024 x 720. The difference between it is much more drastic than the difference between the two other examples, as you can see.)
Different companies have different takes on this problem, though. ComiXology (where Seven Seas sells its manga) uses an image quality that’s comparable to ours. But as you can see above, this causes volumes to have a pretty hefty size, about 200 megabytes.
Meanwhile, SuBLime crams whole volumes into 40 megabytes – and DMP’s eManga into as little as 30 megabytes. This is also apparent in the image quality, unfortunately.
Not that pretty, I’m afraid. Ebooks published in the Kindle Store are thankfully a bit better quality, though they can’t compete with ComiXology in that.
It’s a bit sad that the two main players in the digital manga field using the download-to-own model are stingy with the file sizes. It’s all the more odd since DMP has quite a decent file size in the titles they’ve published in ComiXology.
We here in the manga business are in a happy position, though. As I mentioned before, black-and-white image files are much lighter in file size than color images. Most Western comics are in color, so they generally have to be much more hefty in the file size front in order to achieve the same image quality.
It’s still an issue even for us manga folks, though. Most iPad owners have the model with the smallest amount of storage capacity, 16 gigabytes, so we knew that by publishing our content in high resolution the file size issue would become a problem very soon.
This is why we decided that we needed to add the feature for deleting downloaded chapters as soon as possible, and shipped that in the first update two weeks ago. Of course, you can always re-download any purchase – for a long offline weekend, for example.