What is Kerning? | The League of Moveable Type
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Micah Rich

Designer, Developer, Founder of The League

What is Kerning?

8 min read

If ever there were a popular question, it’d be that. With or without a curse word, it’s a question that we’ve gotten asked countless of times – “What is it? Do I need to understand it? How’s it work?”

Kerning is an essential part of finishing a good font — it's the spacing between a specific pair of letters. A type designer who's making a font will often (though not always) build kerning pairs into a font file, if they find two glyphs next to each other with irregular spacing, to improve the spacing between that pair.

Notice I use the word font, as opposed to typeface; that’s because I’m about to explain what kerning is – in terms of software, and how you use it.

Now, I don't want to get too bogged down in terminology from 100 years ago, but let's start from the top, to give a little context —

The Shortest Possible History Lesson™:

Long ago, in a galaxy that looks suspiciously similar to ours, people printed stuff by placing tiny little chunks of metal (that were molded into the shapes of letterforms) onto a plate, then covered 'em with ink & pressed 'em into a piece of paper.

Back then, a typographer’s job was to do the same thing you do now (choosing excellent fonts for the piece you’re designing, and laying it out in a beautiful and readable way) – but the fact that they had to arrange each individual letter on the page meant that they were ultimately in complete, precise control of spacing.

Nowadays, of course, we have InDesign and Photoshop, and even Word & Pages.

But as difficult as it sounds to have to arrange each of those individual letters, there’s a skill that came from it that we just don’t really get taught the same way typographers of yore did.

Most of us just haven’t been taught the skill of determining optimal spacing between each letter.

Optimal spacing — why on earth would I need to adjust spacing between two specific letters?

For the sake of discussion, let’s just say “optimal” and “readable” are the same. We're talking long-form text here, so that's pretty reasonable.

So the thing is — not all letters are weighted equally. And you can often feel it.

When you’ve got a capital T next to a lowercase o, there may be a bit of funny negative space there that just doesn’t quite flow as well as it's other letter-friends. I like to make the analogy that it makes it sort of wobbly, like something is about to topple over, or something's being pulled or pushed unnaturally.

There’s sometimes too much negative space next to a uppercase T, for instance – that’s just how it works, thanks to the shape of the letter.

For some situations, you're going to notice something funky and want to fix it yourself. Especially when you're faced with giant headlines, where there's a lot of focus on a few super-large characters, it's good to step back, squint a little and try to see if any negative spaces feel uneven.

You're looking for consistent color, as type designers call it — not color as we usually describe it in black, white, or red, but color as a specific type design term, meaning even-ness in spacing. We'll dig into that in a lot more detail in another article, for sure.

Do I have to kern all my type, every time?

As a designer, your eye will, over time, start sensing when that spacing is off, but unlike the typographers of old, most of us just weren’t trained with that detail — it comes from experience, and setting a lot of type over time.

The magic of modern type tech, though, is that now, fonts – i.e. the piece of software you install that enables you to use a typeface – most often come with special rules that the type designer has already determined for optimal spacing.

A majority of fonts you have probably already have kerning pairs built in.

Do they all? No. Do most? Yes.

How can I tell if a font's already been kerned?

There are a few easy ways to tell if the font you've got's already got kerning pairs. Some font sites will tell you upfront what features a font has before you download it. There's awesome sites like Wakamai Fondue (weird name, awesome tool) where you can drop a font in and see whether it's got a feature named "kern".

Plus, in tools like Photoshop or InDesign, there's a toggle in the type panels that let you turn features on-and-off.

Above is an example of Orbitron with kerning shut off and then turned back on. I didn’t manually adjust that spacing, though tools like Photoshop & InDesign do let you, if you get into a situation where you need to.

In general, the type designer’s kerning suggestions are your friend. He or she has most likely spent a great deal of time & effort going between individual letter pairs and tweaking spacing with his or her trained eye – use that to your advantage.

How do I turn on built-in kerning?

It depends on what you’re using, of course.

Adobe Suite – Photoshop & Friends

If you’re using Adobe InDesign, or Photoshop, or Illustrator, it may actually already be on — but may also be turned on with settings you don't actually want.

Open up your character palette, and look for a symbol that looks like a (hover over, and a tooltip will say “set the kerning between two characters”). This is different (and next to) a tool to help you adjust tracking — which is another whole article we'll get into another day, too.

It works by putting your cursor between the two characters you'd like to adjust, and then you can type in numbers or use the arrow keys to change positively or negatively — to increase space, or decrease space, respectively.

But important note: if you're not manually adjusting a letter pair — use Metrics.

This is a weird and often misinterpreted feature of Adobe's suite; despite the fact that Optical sounds way better, it’ll actually ignore the font’s embedded kerning and apply it’s own mathematical ones. It's choosing between a generic computer algorithm, or the attentive decisions made by the person who made the font — which is kind of a silly choice. So choosing Metric actually makes sure you’re using kerning that was suggested by the designer.

Browsers & CSS

If you’re making a website, using CSS, the cautious designer’s best bet at the moment is to set text-ren­der­ing: optimizeLegibility; for headings, and leave the body as-is. Which is only because some browsers still have one or two tiny bugs about it, and it can slow stuff down a bit for mobile phones.

There's a lot more detail, if you're interested in diving deep, between this great article over on CSS Tricks & in an article over on Typekit's blog — which, fair warning, might be more overwhelming than you need, but certainly has research & smart people behind.

Microsoft Word

If you’re using Microsoft Word, I'd recommend turning off your computer immediately before it's too late.

Just teasing (sort of) — but, if you have to, I’m told kerning is shut off by default, and you have to find the Font Window, open Advanced, and check a box that says Kerning for fonts XX points and above. Set it to 8 or so, because you probably won't be using type smaller than 8 points.

And that's what we kall kerning.

So there you have it — designers & future designers, that’s the barebones of keming. Just kidding. But at least you can finally relate to that one XKCD joke.

Getting into how to set up kerning in your own font is a much longer tutorial for another nerdy day; possibly it’s own chapter in a future font book. But hopefully that gives you a little insight into how to make good use of the kerning that’s there, why it is what it is, and how to start workin with it yourself.

This post was inspired by an awesome snippet from our Insta feed: