|Reality becomes fantasy|
How to be a Retronaut, a site I've taken to regularly visiting, has a post called 1950s pin-up girls before & after that has a series of nine pictures showing the photograph an artist used to create a pin-up girl illustration. The picture above is a sample. Visit the site to see the rest.
The article has no comments attached, just the pictures. However, if I read the signature correctly, I think the pin-ups are the work of Gil Elvgren (the link is SFW). He worked for a Chicago Ad agency that did a lot of work for Coca-Cola. At the agency he was mentored by the artist who created the familiar Coca-Cola Santa Claus ads.
UPDATE: Yes, it is the work of Gil Elvgren. I found a few more which I've added after the jump.