changing backgrounds

[scarlet artemis]

I have hired a studio for a pinup shoot in late July. The studio has a parabolic, soft boxes and a snoot etc and a white cyclorama we will be shooting against - there is a paper backdrop wall that has a green screen and white, black and blue photographic papers on a roll.

My dillemma is that most retro pinup pictures have some sort of pastel pink, lemon, green or blue background. At the moment I am able to only shoot against the white cyclorama which will result in images that are a bit vanilla. I can't afford to spend $480 on 4 backdrop rolls, the studio cost is $500 for the day as it is, plus I've bought the wardrobe for the 5 models.

Does anyone have any ideas or tips for changing background to another color in photoshop elements 10 or lightroom 3? I have tried doing the Ken Fong thing using gels and custom settings on my camera, but it wasn't the effect I was after. I want a simple pastel background. Pinup lighting is quite flat diffuse light, so the girl will not look 'cutout' against a photoshop applied background as there are very few shadows on her. If anyone has any ideas I would obliged. Thanks.

[ameerat42]

It doesn't sound too difficult, BUT, any sort of a picture of the setup to give us a starting point?
Am.

[Warbler]

My limited experience with changing background colours tells me it easier to change from a bland grey backdrop to colour than the other way around. Some light always bounces back onto the model and carries with it the colour of the backdrop. Decontaminating that colour can be very iffey.

I'd be shooting them on a grey or white backdrop and then replacing that in PS. You need to create a layer mask in PS to do that. Around the hair will be the fiddly bit. Youtube is rich source of "How To" videos, especially for Photoshop techniques.

[scarlet artemis]

Thanks to you both for answering. Warbler, if I create a layer mask and change the overlay to the color I want, if I then set the opacity to 50% and erase over the top of the model that seems to work - its going to be fiddly processing so many frames as each girl will have 5 outfits and 20 poses for each outfit shot in exposure brackets....but it will be worthwhile as I have plenty of time but not the sort of money I wished I had! Thank you.