My wife usually gets her hair “done” in a salon,. When she gets home, there are inevitable complaints that it “looks different”. Of course – the lighting is changed .

There have always been different light effects – sunset, noon, overcast. And artificial from candles, gas jet, incandescent. In the era of LED, any “temperature” of red or blue or green or yellow mixture can be served up, bright or dim .

We deal with all this amazingly well. Red usually looks red. A landscape picture resembles itself in almost all conditions. But that should indicate to us just how amazing our vision is – both raw data gathering and interpretation .

Painters always knew this. Patrons who bought things done under “Northern light exposure” in studios rarely hung their purchases under similar conditions. Poor artists’ dimly lit barns had different lighting then when the work is hung in a brightly illuminated museum. And forget trying to recreate the conditions of “plein aire” .

My lesson is that much of our life is like this. We may think things are exactly the same, but only because our brains automatically adjust to what are objectively quite different events. It’s part of our amazing ability to compose and generalize, the core of our knowledge. 

Not quite obvious, and easy to ignore. Until the hair looks entirely different …