Brecht’s banishment of coloured light from the theatre certainly required explanation and of course received it from the Meister himself in his theoretical essays: the theatre should reveal, not conceal, illuminate, not leave in obscurity, demonstrate openly, not beat about the bush, etcetera etcetera. His old friend Caspar Neher had another explanation. After World War I, in the inflation period, power shortages were rife, and radically affected the theatre. Should they shut down? Revert to candles, gas, or arc lamps? Well, the more affluent theatre people had cars, and the big sporty cars of the era had external headlights, rather easily detached. Neher invented ‘Brecht lighting’ by detaching headlights and using them as stage floodlights. This lighting was (1) white and (b) very intense. (a) plus (b) equals BB lighting.
Eric Bentley, The Brecht Memoir