dodge and burn layer question

Greetings,

As a photographer a standard way of doing dodging and burning is to make a new layer, change the mode to soft light, and check the fill with 50% gray box. Then use brushes with black or white to burn or dodge. This works great except it creates another layer that doubles the file size.

Is there an adjustment layer method to burn and dodge as well as the above technique, but not increase the file size like that technique?

Thanks for any help you can give.

A Levels or Curves layer would do the trick, I suppose. My workflow is usually 16-bit ProPhoto, and after such an adjustment (dodge burn layer) I´d simply flatten the image after verifying my results.

Only problem with that is that your changes are permanent. Ideally I would like to have a file that I can come back to and tweek that D&B layer if needed.

If its not on a separate layer then it is a part of the base image, no? Storage is cheap (CD/DVD).
If the overall file size is slowing down your computer you can save different versions with some layers merged in order to reduce the file size of particular versions of your image.

Oh, I call it a work file. The RAW is still pristine, ready for another go years ahead.

Mathias