Back in the seventies, and even into the eighties, there was a certain type of border style that was popular, especially in magazine design (e.g., Rolling Stone
where they had a scotch rule frame on every single page). It is typically made up of a thick and thin pair of rules, placed closely together. In the most common ones, the thick part is 3-4 points and the thin part is a hairline, but other styles were possible, such as having the thick part very thick. You still see them, but they seem to have gone out of style by the nineties. I think they were also popular in the 1920s.
I've always known these to be called "scotch rules". I don't remember where I learned this term. I was wondering where it originated or if it's even used anymore. Searching the internet was useless, turning up things like rules for making scotch drinks, or playing hopscotch, or (if I add "type" or "typographic") scotch typefaces. Nothing about rules as in "borders".
In the 1923 ATF catalog they are found in the brass rules section. Lots of styles were available, including the above, but they are just called "brass rules", with no special name for this particular style.
Does anyone know where the term "scotch rule" came from? Do people still call it that?