Optical Vs. Metric Kerning

I think the main issue is people are using optical kerning when what they really want is optimal tracking.

Here's a link to Michael Murphy's website The InDesigner and two webcasts about type and tracking. Very talented, articulate guy.

re:<br /><br />(2) I don't have the same faith or experience in near perfect optical kerning. In general, I find it sets type too loose.<br /><br />But you can always overcome that with tracking <grin><br /><br />(3) As I've said before, this isn't an error with the metrics - it's simply true optical kerning, where the space between letters is balanced. You may not like it, but that doesn't make it an error. <br /><br />Of course it's an error. It's a sucky error so bad that the person who made the mistake should have been fired forthwith. Fortunately, it is an error that is largely restricted to Gill Sans and so not a good general argument. I guess I must have been using Gill Sans on some job back in the 90s when this first came to my attention using PageMaker.<br /><br />Dave

In reply, I'd say that:

(1) I prefer to set tracking explicitly by style, not hope that some algorithm is going to come up with the right amount.

(2) I don't have the same faith or experience in near perfect optical kerning. In general, I find it sets type too loose.

(3) As I've said before, this isn't an error with the metrics - it's simply true optical kerning, where the space between letters is balanced. You may not like it, but that doesn't make it an error.

(4) I don't see any major speed loss with optical kerning, and this is not an argument I advance against it, though in scripting I accept it may be an issue.

(5) In such cases, I can see the value of optical kerning for those who can't or don't want to manually kern, but most discussion and advocation of optical kerning in these forums seems to centre around just turning it on for long stretches of standard text.

(6) I see such instances as an argument for a kerning editor, not optical kerning.

It was five years ago and I've long since lost the specifics. But it came down to:<br /><br />1. Optical kerning, in effect, has built-in tracking, so when you use it for different sizes of text, it automatically adjusts without the need to tweak the tracking.<br /><br />2. Optical kerning works on all pairs and only occasionally produces a bad pair. Metrics only apply to the pairs the designer attended to.<br /><br />3. Metrics in some fonts (and I'll grant I might be a bit over-sensitive to Gill Sans, which is the worst offender) cause spaces to disappear at the end of sentences when the next sentence starts with a T or W.<br /><br />4. There is no discernible speed difference between metrics and optical (I mention this only because Richard keeps implying that your computer is all but consumed by the processing power that optical kerning allegedly uses).<br /><br />5. In the work I was doing at the time, it was frequently the case that I was working with text that had mixed styles, mixed fonts and mixed sizes, so the fact that optical kerning kept on trucking in those cases was relevant to me.<br /><br />6. In the final jobs I did with PageMaker, I went so far as to generate a PalatinoPDS variant of Palatino to address some of its metrics weaknesses. I forget which changes I made now, although I do recall that <open-double-quote><capital A> was one that look plain awful in the font because it was missed by the designer.<br /><br />Dave

>I did a lot of careful looking at optical vs. metrics and concluded that each had its strengths and weaknesses

You see, I'd be interested in reading those lists, rather than just assertions that optical is best. To me, the weakness of each is that they rely on algorithms to generate an aesthetic result (something not best served by programs), but metrics has the added avantage of a trained human eye being run over the pairs.

>However, kerning for text at display sizes is quite different to that at body sizes, and the metrics at that point are probably way off.

Richard, I don't follow this. Why does kerning have to change with point size? If there is a correct visual amount of space between letters, why does this suddenly become wrong when you increase the point size? Yes, there is the separate issue of tracking, but that is a text-wide setting.

In PM's day, the computers were slow and Export Kerning had to be applied as a user initiated process; if memory serves, it didn't survive editing, so you had to do it as the last thing you did. So, it was nowhere near as convenient and optical kerning is now.

A few years ago, I did a lot of careful looking at optical vs. metrics and concluded that each had its strengths and weaknesses and the the weaknesses of optical were easier to overcome.

Dave

>Improvements come from the fact that optical kerning keeps on working when glyphs from different fonts are next to each other, or different styles of the same font or even different sizes

These are very specific circumstances and I don't see that they justify the blanket assertion that optical kerning is "often superior and definitely the way to go". Frankly, when I do get glyphs from different fonts adjacent to each other, I prefer to kern them manually.

>InDesign's optical kerning didn't exist when a lot of these fonts were designed.

No, but Kernus and other kerning programs did and I haven't heard that they've been dropped wholesale for ID's kerning.

I don't recall this sort of devotion to optical kerning when it was present in PM as expert kerning. I've said it before and I'll say it again, if it were called "computer kerning" and metrics "designer kerning", I think that would have an effect on people's preferences. I strongly suspect that most people who always use optical have not done anything more than cast a cursory eye over the results before and after and simply think "optical" sounds more designer-ish than "metrics".

>unneccesary busy work.

How is setting a paragraph style to use Optical rather than Metric kerning "busy work"? It is a trivial one-time setting...

Fonts are designed (for the most part) to be used at body copy size and the metrics are set accordingly. It's when they are used at larger size that the metrics fail visually and one resorts to optical.

Got this from Graphic Design Forum:

<<Every font has in-built data on kerning pairs between its letters. For most cheap/free fonts, though those kerning pairs are somwhere between awful and non-existent. For a font from a major type foundry, like Trajan, there will be an exstensive set of kerning pairs. That's what you get if you apply metrics. Those kerning pairs were created by an expert font designer, and should get you good results...

at the size they were designed for.

Which is generally around body copy sizes. However, kerning for text at display sizes is quite different to that at body sizes, and the metrics at that point are probably way off. That's where the optical setting comes in. There, Indesign tries to guess the correct kerning based on optical weights of the letters. It will usually get you far closer to correct than metrics at display sizes, but under most situations hwere you'd use optical, you should probably expect to need to do at least some manual kerning as well.>>

What are the "body" sizes those of you applying optical kerning to paras? I don't consider anything beyond 11-12 point body copy.

Maybe it is subjective but I think optical kerning applied to body copy is a lot of unneccesary busy work. My gut feeling is anyone applying optical kerning to an entire paragraph is using it in lieu of proper tracking which is the spacing between all letters. Again, this can be adjusted in ID prefs or within style sheets.

Improvements come from the fact that optical kerning keeps on working when glyphs from different fonts are next to each other, or different styles of the same font or even different sizes, and, of course, it works for every pair in the font, not just the ones the designer bothered with. Frankly, from what I've seen of designed kerning metrics, there's a lot of energy expended for little real value compared to optical kerning. InDesign's optical kerning didn't exist when a lot of these fonts were designed.

But to each his own.

Dave