This poster featuring The Doors, was made in 1967 by a company called Saladin Productions. Like many of the “Headshop” posters made in the late 1960s to satisfy the American teenager poster craze, not much in known about Saladin - generally these companies were in business for a short time and then moved on to chase the next fad.
As with many of the Saladin posters - and there were many - the company produced posters at least through 1973 - the artist is not credited. This Doors poster was similar to a line of other groovy posters for bands like the Jefferson Airplane, the Electric Prunes, the Byrds, the Buckinghams, Buffalo Springfield, and the Monkeys. They even produced a psychedelic mandala coloring book in 1967.