If you do what I do—type the kerning value in—you never see the line.

I usually have ten characters in the Kerning Window at one time—e.g., AABACADAEA—so I can type and tab in rapid succession through nine pairs. Sometimes, my original guesstimates are off, but it only takes going through a few of these strings to get the hang of guessing more or less correctly.

If I get it wrong, I just continue through the text string to the end, and tab back to the trouble spot to tweak. Hence, no lines and a brisker pace.

Hey thanks, that's really helpful.

Btw, what's your approach to viewing size while kerning? e.g. In Fontlab's Metrics window, I tend to view the type big (128pt) so I can accurately judge spaces, but I sometimes wonder whether it's better to kern at sizes closer to reading size since that is the intended end-use of this typeface...

Font Lab Studio > Preferences... > Metrics window > uncheck Highlight all kerning pairs

ATF, you can't kern at small sizes in the metrics window, because the coarse pixel grid of the screen won't display many kern values and will round others in misleading ways. The larger the type, the closer to native resolution (UPM), the fewer rounding problems and the less distortion. If you want to see the kerning at smaller sizes, back away from your screen.

Wayne: ‘I sometimes wonder whether it's better to kern at sizes closer to reading size […]’
 
In my opinion kerning is a refinement relative to the spacing, irrespective whether the typeface is meant for larger or smaller point sizes. This automatically implies that kerning can be defined at the highest (read: most convenient) resolution.
 
FEB

Eliason, thanks for your suggestion but all it does is turn on/off the small blue horizontal lines beneath each pair. Not to worry, Nick's suggestion to kern in strings is proving most useful. Thanks too, John and Frank... I was worried that my habit of checking text strings at large sizes might be skewing my perception of the spacing that is required at reading sizes... but you have put my mind at ease

Wayne