Optical Vs. Metric Kerning

The result of optical depends on the font and the fontsize. Some fotns handle it better than other.

I use optical for everything -- when I remember.

Dave

I believe that metrics kerning leads to faster text flow and redraw (Indesign doesn't have to do the analysis work itself), and probably for highly-designed fonts where overlaps are expected (like scripts with connecting strokes), metric may be more accurate IF the original designer created the font correctly. Kerning is an art, and optical kerning is, in a way, turning over that art to computer algorithms instead of leaving it to the font designer. Like any such endeavor, this can be better or worse depending on the care with which the particular font was created.

Also, metric kerning can't kern pairs in which one character in the pair is in a different font, italic or bold, or superscripted or subscripted. So if you've got a lot of text variables like P _a, you may be better off with optical.

Rodney

Optical is good for headlines and possibly pull quotes. Short lines only. Don't use on paragraphs.

Personal preference really. Personally I always use optical. Some never do and prefer to do it themselves or use metric.

Optical kerning uses the form of the characters in the actual font and sets the kerning according to that for the best result. Metric kerning uses the built in kerning pairs in the actual font to set the kerning and where ther is none, you do it manually.

Or as the Help file explains it:

"Metrics kerning uses kern pairs, which are included with most fonts. Kern pairs contain information about the spacing of specific pairs of letters. Some of these are: LA, P., To, Tr, Ta, Tu, Te, Ty, Wa, WA, We, Wo, Ya, and Yo.

InDesign uses metrics kerning by default so that specific pairs are automatically kerned when you import or type text. To disable metrics kerning, select "0".

Optical kerning adjusts the spacing between adjacent characters based on their shapes. Some fonts include robust kern-pair specifications. However, when a font includes only minimal built-in kerning or none at all, or if you use two different typefaces or sizes in one or more words on a line, you may want to use the optical kerning option."