Not everyone who wanted to advertise could afford specially made and designed slides, but luckily there were D.I.Y. options from as early as the 1910s. While the exact date of our Radio-Mat patented slide kit is unclear, mentions of Radio-Mat kits can be found as early as 1918.
A letter to the Library Journal, from June 1918 reads, in part, as follows
Y.M.C.A. secretaries are glad to run in their motion picture machines slides calling attention to the library. It is worth while to give each brach one of two titles in numbers sufficient to justify their being featured on slides thus:
READ “THE FIRST CALL”
BY ARTHUR GUY EMPEY
20 COPIES IN THE BRANCH
LIBRARY IN THIS BUILDING
GET A COPY OF THIS BOOK
BEFORE YOU LEAVE TO-NIGHT
AMERICAN
LIBRARY ASSOCIATIONA slide like the one here given can be quickly and easily made on the typewriter by using the Radio Mat Slide made by the Radio Mat Slide Company of New York.
(credit: American Theatre Architecture Archive, Theatre Historical Society of America)