Re: 18% grey
Re: 18% grey
Bruce Lindbloom calculated that gamma 2.46 pegs 18% at L50
While this was a great index for scanner calibration, digital camera tone compression into 8 bit often means that the midtones get compromised from accurate reproduction to perceptual repro for high key, low key and mid key "looks". Hope this helps.
- Jon
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On Apr 8, 2005, at 2:11 PM, eugene appert wrote:
<x-tad-bigger>Can anyone tell me if there is a standard consensus about what Lab Luminosity value a Kodak 18% grey card should yield? I know there is a formula for calculating L* from density. I saw it once but couldn’t understand it. But seeing it showed me that L* could be directly translated into density. While testing my camera, which I suspect is slipping off the mark, I discovered that the best exposure of a Kodak Q14 greyscale target is not the same exposure that produces L*54 in a 2.2 workspace or L*61 in a 1.8 workspace after conversion through Camera Raw. Now I am wondering if the Kodak 18% grey card is applicable to digital capture. Is there another reflective grey value that is used to calibrate digital cameras and if so, is it standard? Or is something else going on?</x-tad-bigger>
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| | >18% grey (From: "eugene appert" <email@hidden>) |