I have a 100ft spool of Double-X type 5222 on a No. 10 spool, that I got 4 decades ago, and it just resurfaced. :)
The emulsion number is 5222-719-183J . Anyone know how to decode the number, other than the first 4 digits? I'd guess the film dates from the late 1950s-early 60s.
I did a few test shots from it, the base fog is pretty bad, but you could see the images.