What percent should an 18% grey card be exposed to?

[Drcoffee]

Is it 50 or 70, I think? and why isn't it 18%?

Jon

 

[Chris Santucci]

The 50 or 70 you refer to would be an IRE value, while 18% refers to a mid-level value of grey as determined by George Eastman many years ago.

The 18% grey card is commonly equated to 50% IRE.

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