How do I alter the Black Balance of a clip in Premier. I have a shot of a person wearing a black shirt and it appears brown, none of the Video Effects seems to change it

You can do as suggested above, but I would go into Lumetri panel with the scopes on and check the RGB Parade and/or Waveform YC (no chroma), and check signal levels first.

And with Vectorscope YUV up, you can see the Hue vector also.

There's a good chance lowering the Shadows  in Basic tab or the Shadows wheel Luma slider (which also moves Black point) will take care of the issue.

If you still need to neutralize color casts, you can use the Shadows Tint control (Creative tab) or Shadow Wheel ( color Wheels tab) to change shadows color.

There's many places online including some decent basics instructions in the Adobe Help system both articles and tutorials.

Also my blog has a number of explanations and demonstrations of what the various Lumetri tools do ... and don't  ... do.

rneilphotog.com

Neil

You use the Luma vs Sat curve in Lumetri.   A curve like the one below will decimate the colour in the shadows:

the white balence will be set wrong in your camera i.e, you had it set to indoors or cloud instead of sunny

example Frogmouth becomes Frogmought

moved to premier pro forum