does it matter if I use black plastic instead of clear plastic with lighting? I'm doing a big pie shoot with my wife and I want to get the lighting just right.

From an aesthetic perspective, covering everything in black plastic will look better. The clear plastic will allow you to see everything you happen to be covering and that could be a distraction. My suggestion, use a clear room, use one corner and cover it in black plastic. Open up your windows and shoot at the time when light is entering the room from those windows. Shooting into a corner has a couple small advantages. The black plastic is reflective. Shooting into the corner will prevent your reflection from being seen in the shiny plastic. The shiny plastic will also act as a very weak light reflector putting much of it's light onto the model. Finally, if you want your model/wife to stand out, avoid dark clothes which can blend into the background. Pay particular attention to the soles of shoes if she intends to wear them, black soles will virtually disappear in a black backdrop. If your wife has black hair you should place a light above her. This will help to prevent her hair from blending into the background. Hope this helps

Sincerely EdR
asplashofglamour.com

If you get the exposure right with black plastic, I think it will look better. Make sure your camera isn't fooled by all the "dark" because most of them will try and lighten up the whole scene, overexposing your model so your model is too bright. If you get it right, you can also make it so that the black plastic all but disappears (underexposed) so that the model, and the mess, is all that shows up, focusing attention on just what we want to see.

Photographing on white plastic is easier, and can produce professional results and even lighting. I'd recommend trying to find opaque plastic so you don't see carpet and wall and electrical outlets through the plastic.

MM