In reply to Slantarant:
Since digital type is all on a grid, a slope of 1/n where
n is an integer is what makes sense. An integer degree
slope produces erratic stair-steps, with no benefit.
Degrees have basically become a dysfunctional legacy.
BTW, for onscreen type the grid is so coarse that
each point size benefits from having its own slope!
In Patria (which influenced Ernestine) the slope of the
Italic is 1/16, which is about as slight as I think one
should go; it's ~3.6 degrees. I could have chosen 1/20,
but the nice things about 16 are that: being a power of
2 it can be halved all the way; and at 12 pt (on Windows)
you get precisely one step (in the middle). Sometimes. :-)
hhp