Is there something I can do to clamp the bright areas that allows adjustment? I can use Proc to decrease the brightness, but that scales the whole range down. It sounds simple, and I think I’m missing something. Maybe a way using the Y value in Swatch?
The moral of the story is “I’m not as smart as I think I am” 
Lars answered your question in the recent journal post!
“It sounds like you want to adjust the gain of the brighter parts of the signal only, without effecting the darker or midtone values. This kind of signal processing involves a non-linear transfer function of some kind. There are several ways to approach it.
One way would be gamma curve adjustment using the logarithmic and exponential processors in DSG3. By feeding luma video thru these processors you can compress the dark values (exponential curve) or you can compress the light values (logarithmic curve.) Try this, and then mix the results with the original signal at varying proportions to dial it in the way you want. Another approach would be to use multiplexing (Switcher) and a comparator (Keychain) to change between two different processed signals, based on the grayscale level of the unprocessed source.”
Thanks, Chad! I hadn’t seen this yet. It’s sure interesting to me, I will give it a try.
Pete
You could also use FKG3 to perform a soft key between two versions of the same signal.
Or use VU005, it gives adjustable nonlinear control over brightness. With neutral “Shape” (bias) settings, it will compress both the light and dark values. But by tweaking Level (gain) and Shape, you can get a variety of nonlinear curves.
If you process Swatch Y out through a module such as DSG3 or VU005, the chroma won’t be affected. This may not be the result you want. Another approach would be to process the RGB channels, for which you’d need 2x DSG3 or 2x VU005.
Maybe the triple function generator would work for this?
Many thanks to all who replied! I will be trying out these suggestions this weekend!
True confession: If I had recorded the video right in the first place, I wouldn’t have needed to ask! 