Michael Ball uses bay rum for Sweeney Todd and a cheap old perfume of his mother’s for Edna Turnblad (Hairspray). Fenella Woolgar deployed Chanel No. 5 (with an extra spritz) for a 1950s snob. David Greig sniffed canned mackereal to put him in mind of the chilly mountains of Scotland. Before playing a homeless man, Arthur McBain sniffed a paper coffee cup after the coffee was finished. David Jays explores the use of aromas, and the emotions they trigger, with these and other actors as well as a ballet star and a perfumer.