It cannot be overstated how important your book cover is. It’s the first impression, the spark that drives a reader to learn more about your book. And there’s one sure fire way to lose that reader’s interest; a cover that is poorly designed or has a misaligned book spine.
I’ve written at length about cover design. So instead I’m going to look at a less often covered aspect of cover creation; the technical build of your file. This includes designing for bleed and correctly placing your spine, as well as the critical task of planning for variance.
What Is A Book Spine?
A book’s spine is the center of the cover, the narrow (or wide) edge where the pages are bound. There are a lot of different ways to bind a book. For our purposes, we’re going to focus on perfect bound books because it’s one of the most commonly used binding methods.
Perfect binding involves milling the spine edge of the pages to create a series of notches. Then glue is rolled over the spine edge and the book block is pressed into the cover until the glue sets. This glued edge becomes the book’s spine.
Cover Maker Best Practices
Your book’s spine is one of the basic parts of a book that can be tricky to design correctly. Even though your book cover has three distinct parts (the front cover, the spine, and the back cover) you need to design the cover as a single, complete file. Here’s a look at a standard, US Trade cover template:
We’re going to break this template down a bit and understand how to build your eye catching book cover. Let’s start with the basic trimming margins.
Books, you may have noticed, are incredibly uniform. Printers achieve this by printing the pages over-sized, then trimming every page to the exact size. The stack of pages, often called a book-block, can be cut down precisely to get the clean finish.
But doing so means some small portion of the page are lost. We call this edge the ‘Bleed Margin.’ You’ll notice on the template above it’s listed as the TRIM / BLEED AREA. What happens is that we print the pages for your book too large by ¼ inch. So a 6 x 9 book is printed at 6.25 x 9.25 and that extra ¼ inch is trimmed away – resulting in about ⅛ inch on each side (this includes the spine side) being cut away.
For most book interiors, this is minor because the pages are white or cream and the contents (your story) is no where near the edge of the page.
Covers are very different. Your cover is going to have art/ink right up to the edge. Which means you’ll need to be careful to plan out your cover with no important content in the TRIM / BLEED AREA as shown in our book cover template.
Bleed & Your Spine
Okay so let’s look at this template one more time.
That purple bar represents where a spine will go in your cover design, but it’s not THE spine for your book. Unless you’re interior file is exactly 22 pages long. In which case, yes this book spine is perfect.
But for most covers, the spine width will vary based on your page count. So you have to create a spine to size based on your book—and here lies the most challenging part of cover design.
You see, the spine itself isn’t really impacted by bleed, but it’s position on the cover is. Even without changing anything about your file, the precise location of your spine can shift very slightly from one printing to the next. This isn’t a print-on-demand issue either, it happens with off-set printing too.
Let’s use this cover I created as an example:
Ignoring the awful colors, you can see how I’ve created the spine as a ‘bar’ down the center of the cover. Here’s another look where I’ve highlighted the exact spine location in red.
When I have this book printed, I naturally would want the RED spine area exclusively on the spine, while the front and back cover feature their own artwork. But in practice that won’t be exactly what happens. We call this variance.
Variance And Your Book Cover
Putting everything we just looked at together, you have a cover that is printed just slightly too big and trimmed down, and a spine set to the center of your cover file. When the edges get trimmed, the exact position of your spine might shift by a tiny fraction of an inch. Like, just the tiniest bit. This is variance. And even being a very small shift, it can be enough to change the appearance of your cover.
And it only matters if you create a cover with a spine like my example above. If you make your spine a stand out color—like cherry red—it’s going to be very noticeable if the spine shifts onto the front or back cover.
These aren’t hard and fast rules, but if you don’t follow them and you spine runs over onto the front or back cover…well I kind of told you so.
If your spin has unique colors or designs, include them for at least ½ inch on the front and back side.
That means creating your uniquely colored spine as a ‘band’ that is included (partially) over the front and back cover. Linen wrapped hardcover books are often created in just this way.
Looks ugly, I know, but you can of course style your cover to look great.
Spine text must be centered and must be small enough to allow at least ⅛ inch on either side.
Our Book Creation Guide includes a great book spine calculator. Size the text to a point measurement that is half or less the width of your spine. I’ll get into how to figure that out next. First, I have one more rule.
Create your book cover as one complete file, not three discreet parts.
For the purposes of sizing, you might make a front and back cover, then layer them over the template to get the spine size. That’s fine. Merge those elements at this point and work on the final cover as a complete file.
Make sure the colors are matched or blended at the spine so that you’re not left with variance ruining an otherwise amazing cover!
Book Spine Formula
Here’s the basic formulat for the spine width in inches, for a paperback book:
(# of Interior Pages / 444) + 0.06 in
Now take note: you do NOT have to use this formula to find your spine size. If you upload your interior file, we’ll generate a template for you that includes the exact spine size based on your file. That said, sometimes you have a designer working on your cover before you’re ready to upload your book. In that case, you’ll want to use the formula to get the right spine size.
Let’s use this formula to think about spine text. For this example, let’s use a 200 page book.
(200 / 444) + 0.06 = 0.51
So that means our spine is 0.51 inches wide. I want to add some text to my spine – like the book’s title and my name. Just like the concern about using a unique spine color, we have to allow for variance when setting our spine text. Imagine how ugly it would be to have spine text bleeding over onto the front or back cover?
Spine Text Placement
To begin with, always center your spine text on the center of your spine—which should also be the center line of your cover file. Working from our 200 page interior file example, we’ve got a 0.51 inch spine.
Text is usually measure in Points (pt).
One Point is equal to 1/72 of an inch. I know, we’re doing a lot of math. I’m sorry.
Let’s say I want my text to be 14 point. A pretty standard size for cover text. If we do the math we get:
14 x (1/72) = 0.194
That means our text is just under 0.20 inches in height. Leaving us that difference between spine width (0.51 in):
0.51 - 0.194 = 0.316
We want to include enough margin to allow for the entire bleed margin, which we know is ⅛, or 0.125 inches, on either side fo the text. Last bit of math, I promise.
0.125 x 2 = 0.25
Since 0.25 < 0.316, we know we’ll have a little more than the bleed size in extra space on the spine. We could probably go up to 16 Point font if we wanted! Giving this allowance means any minor variance in trimming at the printer won’t cause your spine text to run over onto either the front or back cover.
Carefully Design, Carefully Review
I know I threw a lot of math at you today. And for that I am sorry. But cover design is an exacting project, in particular because the actually printing and trimming is, by it’s nature, inexact. The margin for variance is very small, just a fraction of a fraction of an inch, but as we all know, your cover needs to be perfect.
Lucky for you, we provide a terrific preview tool to review your cover after you upload it. Here’s what my cover looks like, uploaded with the spine for a 200 page book, spine text at 16 Point:
It’s a little tough to see, but the ‘Folds’ are showing right on the edge of the spine as blue, dashed lines. Based on the previewer, I can see that my spine placement is perfect!
Of course there may be some variance, but with with location of my spine text providing ample room on either side, I can rest assured that my spine will print well.
Book Spine Best Practices
It might seem a little tedious, but paying careful attention to cover design is worth the headache. With the potential for very slight variance in printing that might impact your spine, you really have to design with this in mind.
Think about variance and bleed when creating, consider what the book spine will look like printed, and please (please!) design a spine the incorporates the front and back cover. Trying to build a book spine distinct from the rest of the cover is a recipe for disappointment.