Thursday, May 28, 2015

Ebook Formats

There is a difference in the ebooks that I'm offering on my store site and those offered through comiXology.

Basically, they're both the same, but only in appearance. Each ebook starts from an uncompressed TIFF file generated from an Illustrator file for each page.

For comiXology, these TIFF page files are combined, still uncompressed, into a PDF file, and that file is uploaded to comiXology (this file is usually about 100Mb for a typical comic). What you receive when you read the ebook in their app is a compressed JPEG of each page. If you download their PDF file, each page is a compressed JPEG (this file will be about 50Mb in size). Note, I've seen these PDFs on pirate sites soon after release (thanks for the support, jackasses).

For my ebook version, these uncompressed TIFF files are resaved as 256-bit PNG files. Actually, sometimes lower -- sometimes 64 or 128-bit. This change in file format does not lower the quality because of the flat digital coloring I use. I then run each PNG through a script I wrote, which deletes any unnecessary data from the file and to further optimize the color palette. After that, each PNG is optimized using a variety of PNG optimizers, like OptiPNG. These PNG files then are combined into a PDF, and, on average, are only 14Mb in size.

Because my PDF files are so much smaller, they'll take up far less disk space and will display much faster. You should be aware however, that each PDF is digitally stamped, 256-bit encrypted and restricted from changing and printing. The stamp will hopefully reduce pirating. Because it's 256-bit encrypted, you'll need an app that can read it (almost all do on all platforms since it's 2008 technology). The restriction of printing should make sense since I don't want individuals printing and distributing my books. Also, the PDFs are only 276 dpi, which is far below what would be required to print something with quality anyway.

2 Comments:

Blogger Brian Ackley said...

Will it display in iBooks as an uploaded pdf on my iPad?

6/22/2015 1:39 PM  
Blogger Marc Hansen said...

Works fine on my iPad 1, so should be fine on all iPads.

6/22/2015 1:44 PM  

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