Why does a digital camera record a Kodak Gray Card (Zone V) as 50% gray?
A Kodak Gray Card represents an 'average' scene of 18% reflectance, but that has nothing to do with a mean or medium on a grayscale. A gray card has an absolute log reflectance density of about 0.75. Medium gray on a 2.2-gamma monitor and a calibrated print thereof is about 0.66. So the image of the card is lighter than the card itself. Why? Who came up with this assumption or standard? Is it a mistake? Did someone assume 'average gray' meant 50%?
Disclaimer:
I'm aware that this is a mainly or exclusively analog forum, but I doubt to get a satisfying answer for my question in a digital forum, since they usually understand little about the Zone System. That's why I post the question here. Besides, I need this to work out some details about making digital negatives, which will be used to make pure-silver contact prints. So, it's an analog question in a way.
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