foot and inch marks
Use straight quotes, not curly
Foot and inch marks —also known as minute and second marks or prime and double prime marks, depending on what they’re labeling—are not curly. Use straight quotes for these marks.
“But back in straight and curly quotes, you told me to turn on smart quotes. So now, when I try to type foot and inch marks, they come out curly, not straight.” A fair point.
Typography purists would point out that proper foot and inch marks have a slight northeast-to-southwest slope to them. True, but those characters aren’t available in many fonts. So straight quotes are the most reliable tools for the job.