Re: Help Selecting Lightness Ranges

George, I can't see an image in your post, but what you want is a "luminance mask."

Typically, you can produce such a mask by loading a given channel as a selection. In the Channels panel, Ctrl+click on a channel thumbnail to load that channel as a luminance mask. Your image may already contain a channel that will produce a useful mask this way, but if it doesn't, choose the channel that's closest, duplicate it, then adjust its luminance range using Levels and/or Curves until it is suitable as a basis for your mask.