If you wish to REALLY DO A SERVICE FOR THE FORUM MEMBERS, what you need to do is go to a photo shop, and buy the 20- level grey scale card that is availible from KODAK. it will cst about $12 or so. it breaks up the white-to-black greyscale inot 20 different levels. I think it may be done at 5% increments, but there is no indication of such. I suspect that it would take $30 of long distance calls to Kodak to find that out. There is probablility that no one there will know the answer to that question,as they have been publishing that card for years for photographic use, when developing B&W photos. All the photographer requires is a understanding of the desired results, not a % number. So, no such calibrated scale emerged. I am quite sure that the exact % values a re known by SOMEONE at Kodak, but who really knows.
ALSO, it is critical to state what projector you are using with your particular 'grey' choice. The absolute black level of the projector in question is the reallly important fact here.
Trust me, manufacturers are paying attention, screen and projector, both. What paints you used to get to the Grey you have chosen, and the method of putting it down as well. The fabric you used and/or the base material. This allows one to compensate to get equivalent results.
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