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Understanding Auto, Optical and Metrics Kerning in Adobe Illustrator


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What is Kerning?

Kerning is the process of adjusting the space between pairs of letters to give them a more pleasing visual flow. Typically, kerning is used in large text such as headlines or titles though it can be used in body text. As font size increases, gaps between letters become more obvious. These gaps are especially noticeable around letters with an outward angle such as V, W and Y. Gaps also occur around letters than have a horizontal bar that creates an open space such as L and T.

Types of Kerning

Adobe Illustrator offers three types of kerning: Auto, Optical and Metrics-Roman Only. The default setting is Auto – also known as Metric (not to be confused with Metrics-Roman only). If none of these options please your inner typographer, there is one more method of kerning you can try... manual kerning. This is an old school, do-it-yourself kerning technique that requires a keen eye for balance of negative and positive space.

Auto (Metric) Kerning

Auto Kerning, also known as Metric, is built into the kerning table of a font. The kerning table assigns values to common problem kerning pairs such as LA, WA, WE, Wo, Ya, Yo, Tr, Ta, Te, and To, among others. You’ll know one when you see one! Illustrator uses this built in code to create tighter and more visually pleasing neighboring letters. Good kerning makes good neighbors.

Optical Kerning

Like Metric Kerning, Optical Kerning is built into a font. However, instead of referring to a table, it uses an algorithm that calculates the space between letters based on their shape.

Optical Kerning is a good choice for fonts with inadequate built in kerning. It’s also perfect for sections of text or words that use more than one font or font size. This confuses Illustrator and it doesn’t know which kerning table to use.

Have you ever had italicized text crash into a Roman figure such as an exclamation mark or question mark? Optical Kerning solves this problem too!

Metrics-Roman Only Kerning

Metrics-Roman Only Kerning made its debut in Illustrator CS4. It is mainly used for Japanese typography, but also adjusts Latin characters and half width Katakana.

Manual Kerning

Good old fashioned manual kerning. There really isn’t anything that can compare to doing it yourself. If done with a trained eye, it can make good line of type a great line of type! It also gives you the greatest control.

How to Apply Kerning

To kern text, highlight the letters that you would like to adjust or insert the cursor between two characters that you would like to adjust. In the Kerning field in the Character panel, choose Auto, Optical, Metrics-Roman Only, or one of the preset values in the Kerning drop down menu. You can also enter your own value into the Kerning field.

To increase and decrease kerning in small increments, use the up and down arrows to the left of the Kerning field. Keyboard shortcut: place the cursor between two letters and use Alt/Option + left/right arrow to increase or decrease the space between characters.

How to Turn Kerning Off

Let’s say you don’t like the kerning adjustments you have made with your text. To undo your kerning, simply select the text you would like to change and type or choose “0” in the Kerning field. The text will revert back to its original spacing.


Now that you are familiar with kerning, I encourage you to try it the next time you set a headline or other block or large text. You will never be able to leave well enough alone again... and that's a good thing!