RGBD

This entire post turned out to be hogwash. I'm wiping it out to prevent the spread of misinformation. If you are interested in why it's all nonsense see my comment below. Thanks to Sean Barrett for pointing it out. The result of all of this has been positive ignoring the part of me looking extremely foolish. RGBM is more useful than I originally claimed because a larger scale factor can be used or if a fairly small range is required the gamma correction is likely not needed.