While watching The Theory of Everything, during a scene set in the 1960s, Steven Hawking remarked to his future wife that peoples' clothing were glowing because of the florescent brightener dyes added to Tide detergent.
It immediately struck me as a likely anachronism, as I remember first reading about them in Consumer Reports in the nineties or later.
When were optical brighteners first added to commercial laundry detergent on a large scale?