This poster and others in the set were researched recently during work on the upcoming book Fire In The Sky; the Making Of Machine Head. You can read more about them (and find out why the example above had to be photographed in a disco in Canada!) on this site. The publishers say they will be releasing the first page spreads from the book very soon, so if you have not yet joined their newsletter service for this title, now is the time to do so as they will get to see the images before they go public. You can find the link on their website.