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| Optically Kerning! How COOL is that! | | Date Created: 06 Feb, 2005, 01:48 PM |
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Before I show you what this is, I need to explain a little bit about kerning. Kerning is the process of adjusting the space between two characters, or glyphs. This space is called a kerning pair. And the space between any two characters can be different than the space between any other two characters. There are many examples, in traditional typsetting, where known problems exist between letter pairs. For example, any time an oblique-sided upper-case letter is used with one of the four rounded lower-case vowels, the appearance of the type is greatly improved if the vowel is slightly tucked under the rising side of the upper case letter in such a way that the two letter spaces are actually overlapped. Because many of these problems are common to the majority of fonts, type designers -- at least the good ones -- have made it a point of honor to build into the font a table of kerning pairs.
In theory, a perfect font would have specific kerning information for each glyph in combination with every other glyph in both upper and lower cases. In fact the more kerning pairs that a font has is usually a good indication of how well crafted that font is. If the type designer has made every effort to insure that there are no unsightly spaces between letter pairs, then that designer has probably included many kerning pair instances. This is a process that takes time and a certain amount of experience.
Note: If you're interested in looking at an example of kerning pair data, you can find an example of kerning pair data on the Adobe site at... http://partners.adobe.com/public/developer/opentype/index_kerning1.html
The downside of many sets of kerning pairs is that this kerning information, which is kept in the metrics tables of a font, makes the font larger in size as a file. There are designers that I know that look at the physical size of a font first to determine if that font has been crafted well enough by it's foundry to consider using before they even try it out. Although this is not a great test of a font since file sizes can also go up when the glyphs have been sloppily drawn and there are NO kern pairs included with the metrics.
"OK... so if you use nothing but good fonts, and the designer who has built the font has taken care of the traditional kerning problems, why do you have to worry about it? Despite the fact that not everyone can choose (or afford) to use only expensive professional fonts from the best foundries -- it's important to remember that even among professional fonts, not all fonts are created equally. Some pro fonts have better metrics information than others. And kerning information provided by the type designer is subjective -- you may not agree with the type designer on how characters should look next to each other. There are also some characters, such as numbers, that type designers don't traditionally build kerning pairs for at all.
It is for these reasons that programs like QuarkXPress and InDesign have always provided you with a means of manually kerning fonts in and out. And these type manipulation features are well used. I work with designers every day. I have seen them fuss with the space between characters on pages that they are working on for hours.
In the last edition of Adobe's Illustrator, Photoshop, and InDesign, we've seen a remarkable step forward in the area of type control. That is, of course, optical kerning. Optical kerning is the idea that any text selected can have a new/alternate kerning information imposed on it. What these Adobe programs do is to look at the physical shape of all the characters selected and then create kerning information based on the characters next to it. The end result is a much more uniform and well balanced text in your documents without the long process of manually tracking certain pairs of glyphs. |
| To use optical kerning in Adobe Illustrator CS and Adobe Photoshop CS, all you need to do is to select the text (Using the Text tool) and choose Optical rather than the default Auto setting in the kerning section of the Character palette (shown below). |
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| The affects are most notable when you are combining characters from different fonts on the same line or word (as shown in the image below). |
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| Adobe InDesign CS is the program where you can get the most benefit from optical kerning. Selecting large text block and applying Optical kerning from the top tools menu (as shown below) will give you a much more balanced look to your type. |
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| If you compare the readability of the text using the normal metrics (lower left) to the text using optical kerning (lower right) you will see that the affect, although subtle is much better. |
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In my experience optical kerning is so good that it should be used all the time. I have a magazine client who's production policy is that optical kerning MUST be applied to all text in all layouts.
So when a font includes only minimal built-in kerning (or none at all), if you use two different typefaces or sizes in one or more words on a line, or if you want to ignore the type designer's kerning information (for whatever reason) you may want to use the optical kerning option.
Good Job Adobe! |
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