Hey all.

So I'm curious about how one would make the "line gratings" that are 2000, 2400 & 2750 lines to the inch. That's beyond the scope of a lens+film or a conventional printer if I'm not mistaken.

Professor Wood's gratings were made by Cornell's Dividing Engine, which I guess is basically a machine that is used to cut divisions in instruments like rulers, sextants, the like.