This was a true double exposure on film. Back in the early days of shooting Rock and Roll if I still had less than 10 photos taken on a roll of film, I would take it out of my camera, and on the leader of the film I'd write how many exposures I took. So the next time I'd advance the film one frame past that number. Well, I forgot to advance the film after either shooting Frank Zappa or Jerry Garcia. Of all of the double exposures this one fit. No, they never played together. Maybe up in Heaven now.