How to use (old) Computer Modern for `math.cal`? And why context matters?

[Paul744]

@Y.D.X If you don’t mind me asking, I am revisiting the kerning issue for Ralph Smith Formal Script (RSFS), from

Ralph Smith Formal Script working in Typst

Note 1: This is probably mostly of interest to those in mathematical circles, as I don’t know if other scientific communities use this font. Note 2: I don’t know if this was already built into the language, but since I couldn’t find it, I decided ot go down the rabbit hole of figuring out how to implement it using .otf files. Because a paper I wanted to try and translate to Typst uses Ralph Smith Formal Script, with notable examples being that the roundface script S is used to denote Schwartz …

After asking around, I learned that TeX has a different method for assigning spacing that doesn’t rely on built-in kerning info. This is how RSFS is spaced, since its .afm file didn’t contain any such info (well, it contained one kerning pair).

Since you pulled from matplotlib, I don’t know if it came with any kerning info. If not, how did your friend get the spacing right? Was it just comparing based on sight with a LaTeX document?