Pinup Photography Lighting is not too different from modern glamour lighting. The environment you are shooting in will determine the exact lighting positioning. In general, you want a well lit scene. When it comes to the post processing, you need your subject well lit so that you can experiment with a wide dynamic range. Poorly lit photographs will not allow you the apply post processing that is an integral part of the final pinup image
To get an old feel to the retro shoot, I like to use a harsher light than a soft-box. I use a soft-box for fill, but I like the pop and sharpness of a silver umbrella. I keep the light modifiers at a good distance to help keep the light even across the model When shooting in studio, you get 100% control of your lights and where to place them. Shooting on location may offer some some other challenges, but if you study pin-up photos and reverse analyse them, you will figure out how to get the contrast and light you want.
Here is one of the best tutorials I ever read on the subject of Pinup Photography Lighting.
One reason why clients and photographers love this style of photography is due to the preparation and care required from both the client and the photographer. All the lighting in the world and all the post work on the photographs will be for nothing if the hair and makeup, wardrobe and posing is not there. Pinup Hair and Makeup are, in my opinion, the first consideration and the most important component of the shoot. Finding yourself a great makeup artist with experience can be tough to find, at a reasonable price, but is money well spent. Pinup Posing is just as necessary as the pinup wardrobe. As the photographer, most of the time, you are the director of the shoot and you should be knowledgeable on all of these parts of the shoot.