Quote: Maybe I'm just too dumb to see it but how can you make a picture darker (or brighter, for that matter)? I have a scene shot in daylight but want to make it look like it was already dusk or evening. How do I do that, please?

One way to do that:

Select the clip > Click Fix/Enhance on top of timeline.

In the Enhance box, check Color Adjustment. Play with the Brightness and Exposure sliders. Lower them to simulate shooting in low light.

How much is up to you to get the result you are looking for.

I played with the Nature clip, Exposure=85 and Brightness= -68 (negative 68) looks pretty much like just before dark (late evening).
Leave the all the other sliders normal.

Maybe not so strong on the Exposure, it makes the sky have noise effects.

Turn off by unchecking Color Adjustment.
Carl312: Windows 10 64-bit 8 GB RAM,AMD Phenom II X4 965 3.4 GHz,ATI Radeon HD 5770 1GB,240GB SSD,two 1TB HDs.

Thank you, that was it!