Originally Posted by b curry
Thanks, but I'm patiently waiting for the answer. The photo doesn't address or answer my question with regards to black-body or white balance. Perhaps you're confused?
I am confused, but that doesn’t take too much these days.
The statement you made that I questioned you said “Sorry, I disagree.
A quality ND filter will reduce the light output without affecting color.
The same cannot be said of the gray screens and there are variances in the effect depending on the gray screen material/color. Any white light area on a gray or so called dark screen will also be gray and measure so. “. I said an ND gray screen will act exactly the same as the ND filter in a perfect room and will give improved performance in a less than perfect room. Don as far as I read agreed with my statement. In Don’s photo example both surfaces were setup to have the same returning FL and show white as white within the same image.
I will attach an image made years ago when the DIY screen alchemists were concocting paint formulas to cover the whole range of ND gray paints to match up to Munsell grays 0-10. These two photos depict a M10 white against an M7 or 8 gray under the same amount of illumination. So the gray sample is at a disadvantage by a small amount. The samples are white on the left and ND gray on the right. The one photo was taken in total darkness while the other had some ambient room lights turned on.
In my case I’m using a M5 screen surface (50% gray/.5 gain) and have adjusted my lumens upward to compensate. My theater can be made to be absolutely dark with zero light admittance and in terms of room reflectance my guess is I’m as good if not better than most commercial theaters and 75% of the way to perfect. So my lights out movie watching is IMO the same as if I had a unity gain white screen using half the lumens or employing a ND2 filter. Where I see big improvements is when I use my theater room to host sporting events or for social TV viewing where we don’t want all the lights out. There is improvement even without bumping the brightness under these circumstances and even greater improvement on some content with bumping the brightness.
The reason you won’t find these screens in “ a SOTA home theater or commercial color grading screening room” is because they are perfect rooms and there is no desire for turning lights on. Of course in such a setting 1.0 unity white can’t be beat. It could be tied but what would be the point in wasting illumination.