numediaman said:
I'm not 100% sure I understand your question, but . . . .
Are you trying to create a picture in layers, with a basic backdrop as the the background image, and then you will layer something on top of it?
To create a basic backdrop you might try to "render" the background by using the clouds filter or some other filter to your liking. You will have to experiment both with the filters, as well as the foreground and background colors (found on the tool bar).
I sometime shoot objects specificaly to use as a background. For example paster walls, concrete walls,bricks, Dense green folage, extream closeups of water color paintings, weathered wood and so on. Once in PS you can radically alter these, give them a color cast, blur them, de-saturate the color and so on. The subject supply a texture but is unrecogizable. One that I like is an under water shot taken with a too long shuter speed I got blurred out yellow fish and green plants. It's just swirls of color.
My wife had to ask me why I was shotting the wall at point blank range while standing in line for a ride at a theme park. I just liked the uneven hand troweled plaster's texture and maybe I'll use it some day as a background for a web page. Ithas a kind of "old world" look.