I immediately tested the 5 year old Sadaf tumeric in my kitchen cabinet using a 3M lead testing kit I happened to have in my house. Thankfully it came out negative!
OK, so the method given for artificial coloring on that page. I'm curious if that works for lead chromate. It seems so simple that it must have been tried in this case? Regardless I'll file it away to at least try on stuff to avoid what colors it can detect.