What are .lf numbers?

Can somebody explain to me what the difference between the regular numbers and the .lf numbers (zero.lf, one.lf, etc.) is? Looking into existing otfs I can see that the .lf numbers usually have a smaller spacing…
What’s the overall difference between the two sets, which one is used in what scenario?

As always thanks a lot!

In fonts, you can have four kinds of numbers:

  • Tabular: monospaces and at cap height. Default in a lot fonts
  • Lining: proportional (one is usually narrower then the zero or eight), at cap height
  • Old Style: proportional; some figures are x-height, some with ascenders and some with descender. They look much nicer in text settings.
  • Tabular Old Style: As the above but with equal width.

Hello George
Thanks for the fast response.
So the default numbers (zero-nine) should have all the same width, while the .lf numbers should be proportional?

I didn’t say that. I said that a lot fonts do it that way. I never do that (except for dedicated office fonts). Depending on the design I mostly use proportional old style figures.