Curvemeister Forum

Jim,
Now if you drag the point around a bit you will see a thresholding effect. 
http://www.curvemeister.com/wiki/index.php?title=Thresholding_Using_Highlight_and_Shadow_Points

This is how you can shop around for the darkest shadow detail.

Remember that you want to find the darkest significant shadow.  It's about finding what makes the image look best not just the darkest shadow.
Greg

Greg,

I didn't know about dragging giving the threshold effect. It's obvious that I'm going to learn a great deal over the next few weeks.
Jim

Grab and drag the right edge of the Lightness curve, and you'll see a black/white version of the image that makes adjusting shadows and highlights easier.

Desert pic redone sweeping across the lightness histogram to adjust foreground,mid and distance.Thanks Mike.