On IO9, Ron Miller has published a selection from his collection of photos of 1970s cosplayers, dating from a costuming epoch where nudity was a lot more common than it is today. Among the clothed pictures (not reproduced here) is one shot of Elfquest co-creator Wendy Pini as one of her own elves.
One thing I noticed in going through the slides — mostly taken at Worldcon masquerades and a few other cons — is the great sense of whimsy that permeated SF costuming decades ago. This is something that seems to be missing, now that costuming is taken so much more seriously.
I recognize a lot pros in some of those old pictures, too — such as Elfquest creator Wendy Pini as one of her own characters.
Oh yeah — I remember another rule. Food was nixed for costumes after one joker covered himself entirely in peanut butter (he was a turd literally and figuratively), which eventually turned rancid after 3 or 4 hours under hot lights. Oh yes, indeedy, those were the days...