Background Contamination… This is a curly one…
Switch your main light off.
Leave your background light on.
Take an incident meter reading of your subject, pointed at your main light – this measures how much of your background light reflects off of your main light.
IF it is more than 4 stops below 18% then, no problem – otherwise, you have a light contamination situation…
For today, that’s what’s in my
Line of Sight.