JungleBook: Simple Kindle eBook Cover Analysis

For those who were intrigued by the Slate article on similar book covers, here is a guest post by Jason van Gumster.

I got myself good and distracted from my regular project work and ended up writing the start of a little script that I’m calling JungleBook. It makes images that are pretty and interesting… and might just provide a little bit analytical benefit.


Story time

Anyone else familiar with Pat David? Well, you should be. He’s a super-cool guy that who runs PIXLS.US, a site dedicated to photography with free and open source tools. However, that’s not why I bring him up. A few years back, he was playing around with using ImageMagick to generate an average blending of images. He’d pull in magazine covers, all the frames in different films and music videos, and portraits of U.S. presidents. However, what really got my attention was a piece he did wherein he averaged the top 50 suggestions that Netflix made to him, by genre.

He did all of that a few years ago, but I only recently stumbled across that work… and it got me thinking (dangerous, I know).

See, as I’ve been involving myself more with writing and designing books, I’ve noticed a few common suggestions keep popping up. One of those pertains to book covers. There’s a [valid] recommendation that if you want your book to sell in a particular genre, go look at the bestselling covers in that genre and recreate their look for your book. The logic behind this suggestion is that people, as purchasers of media, aren’t particularly interested in things that are new and wildly different, regardless of what they say. This is especially true of genre readers. They may appreciate original perspectives after purchase, but before they buy, their goal is to re-experience what they’re already comfortable with. You want to design a cover to meet that expectation.

So when I saw Pat’s Netflix piece, it got me curious. What if I used that process of averaging images on ebook covers in categories within the Kindle store? What would it tell me about color choice and composition for various genres? I had to find out.

However, there’s a problem. I’m lazy.

Going through each genre on Amazon and manually downloading the top 50 book covers in each one would be a lot of work. Boring, tedious work. So I did what any lazy person does… I reached for technology and wrote a little Python code. Amazon, being a technology company, has developed a nice, convenient API (application programming interface) for their store… a way for code to talk to it. The idea is to make it easy for advertisers and sellers to use Amazon’s data on their websites for easy purchasing. So with a little light research on the API, I was able to cobble together a handful of lines of code that would suck down the top 50 ebook covers in whichever genres I wanted. Then I’d just need to use Pat’s basic technique and make those averages (also scriptable). Sweeeeet.

The results

The results (as shown in the top image of this post) might just appear to be an interesting mess (as a friend of mine said, “doesn’t it just mean that all book covers look alike?”). However, if you look closely, there’s a lot of cool things that can be learned. We can start with the obvious stuff. For instance, titles and author names are typically at the top or bottom of covers in most genres. You can tell that by the large horizontal blocks of vertical lines that are focused at the top and bottom of most of those images. Nonfiction and Humor covers tend to use brighter colors overall. Westerns use mostly brown and orange hues (sand and the dusty plains… go figure). Stephen King shows up in the Horror genre so much and his titles are placed with enough consistency that it very easy to see a giant KING at the top of that genre’s composite.

King is big in horror

But there are some unexpected and interesting things learned from this exercise, too. Take a look back at the combined image for Westerns. See that dark, strong horizontal bar across the bottom? How much do you want to bet that a lot of Western genre book covers feature a wide landscape or sunset/sunrise shot? And it’s easy to see that most comics and graphic novels put their titles at the top of the cover, but who would’ve guessed that yellow would be in so much use in that category? It’s even more striking when compared against the other categories.

Notes on horror and comic covers

Here’s a fun one: check out the mix from the books in the Mystery, Thriller, and Suspense category. There are a four very distinct horizontals almost evenly spaced along that image. Books in that genre don’t stick to keeping their titles at just the top and bottom. Oftentimes, those covers are very sparse on imagery and consist of just the typography over the whole cover. Nonfiction covers are similar, but the titles tend to be less bold, so you don’t end up with those four distinct regions.

Typography on Mysteries, Thrillers, and Suspense books

My favorite composition thing to note comes from the three fantasy-based categories: Science Fiction and Fantasy, Epic Fantasy, and Dark Fantasy. These three have a very noticeable compositional triangle on their faces. Romance, Westerns, and Horror have similar focusing, but the shape is more oblong than triangular.

Shapes reveal in compositions

What’s next for the JungleBook script?

So this little chunk of code’s got me some pretty cool results… and pretty quickly (laziness FTW!). I’ve gotta say I’m pretty happy. Once I clean it up a bit, I’ll probably push Junglebook to my GitHub account and share it around. At the very least, that’ll make sure it doesn’t get lost on my hard drive. In the best case, perhaps a better programmer than me can find a cleaner, more elegant way to generate images like this… or even more interesting images that reveal more design hints and tips.

Of course, now my mind is spinning with all kinds of other cools things to look into. For instance, Amazon updates the bestsellers list on an hourly basis. What if I tracked the number one book in each of these genres for a month and averaged those together? What might that tell us? Or consider the fact that I’ve only looked at a pretty small representation of all the different categories in the Kindle store. What if I set up a website that would generate a top 50 averaged images for any category on the fly per user request? Or what if I did these averages every day for a month and then animated them to see how the average changes throughout the year? If I did it for multiple years, we could see if there are seasonal shifts and trends.

There are so many different possibilities here that I’m not entirely sure where would be the best place to start. So guess this is where I drop in the question(s): What would you like to see? What would be most useful? What do you think I should do next?

reposted with permission from MonsterJavaGuns

Nate Hoffelder

View posts by Nate Hoffelder
Nate Hoffelder is the founder and editor of The Digital Reader. He has been blogging about indie authors since 2010 while learning new tech skills weekly. He fixes author sites, and shares what he learns on The Digital Reader's blog. In his spare time, he fosters dogs for A Forever Home, a local rescue group.


  1. Felix31 August, 2015

    And that’s why I disregard all advice about getting “professional” covers and always roll my own. Maybe they won’t look all slick and polished… but at least they’ll stand out, simply by virtue of not being same-y. And I’m willing to bet that readers care more about the blurb and sample anyway.

    Still, seriously? I remember a similar experiment done a while ago with movie posters, and they were even more uniform. Frighteningly so in fact. Entire industries’ worth of graphic design professionals, and we get *this*? So much for money spurring creativity…

  2. Jason van Gumster31 August, 2015

    @Felix: But that’s the thing. Consumers don’t want something that stands out. They buy looking to have their expectations met. And they won’t get to read sales copy or samples if they don’t first click on the cover. The apparent “sameness” that these averages show is a confirmation of consumer buying habits. It’s *not* the fault of designers.

    That said, there’s actually some interesting variations in there regarding color and composition based on genre that are at least interesting… if not somewhat illuminating to a designer.

    Also… thanks Nate for re-posting this (though it’s MonsterJavaGuns, rather than Java Monster Guns 😉

    1. Nate Hoffelder31 August, 2015

      Fixed it.

  3. DavidW1 September, 2015

    Okay westerns:
    Elmer Kelton covers, a lot of them do not have horizons.

    Okay MST:
    Craig Johnson covers, nice cover art not just text

    Okay SF/F:
    Alastair Reynolds covers, no triangular presentation

    These are just quick examples, but it’s easy to find many more. All of these supposed conventions are just bs. Just an example of drawing false conclusions from limited data.

  4. DBW Spotlight Launches Today | Digital Book World1 September, 2015

    […] A Kindle Ebook Cover Analysis (Digital Reader) One writer conducted an experiment to analyze book covers. “What if I used that process of averaging images on ebook covers in categories within the Kindle store?” Jason van Gumster writes, referring to a previous analysis of Netflix suggestions. “What would it tell me about color choice and composition for various genres? I had to find out.” […]

  5. Jason van Gumster1 September, 2015

    @DavidW, granted, nothing is definitive and covers need to be designed to fit the content of the book as well as its genre. And exceptions can always be found (especially when the analysis isn’t presented as rules, but merely a [hopefully] helpful guide).

    HOWEVER, it’s also worth mentioning that none of the authors you’ve mentioned are in the top 50 of those respective categories. I’m not saying that having different covers would necessarily put them there (it certainly takes more than just a good cover to make a book rank well). People other than myself regularly make the recommendation that authors should look at the covers for the top 10-100 books and make their own designs meet those expectations. My little study merely confirms the fact that there are trends within the top 50 and hints at what some of them might be.

  6. Thinking About Design3 August, 2017

    […] “JungleBook: Simple Kindle eBook Cover Analysis” on The Digital Reader […]


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