1. Make a portrait where the person’s face and the background are the same exposure.
2. Make a portrait where the person’s face is exposed one stop under and the background is normally exposed. Drop the power of the strobe by one stop keeping the f stop the same.
3. Make a portrait where the person’s face is normally exposed and the background is one stop under.
4. Make a portrait where the person’s face is normally exposed and the background is two stops under.
All four should be photographed in exactly the same place to make it earier to compare the results.
This is a test for your reference and should be laid out accordingly.
Print your f stop and shutter speeds.
Subject should be 2 or 3 stops darker than background.