What HDR? Get a dark room. With projectors, HDR of any variety works best when viewing at night or in a dark room. HDR can give you blacker blacks and more brilliant highlights than SDR for a wider tonal range. However, to see the difference on a projector you must be viewing in a very dark room. Even a small amount of ambient or reflected light will compromise black levels, reduce contrast ratio, and hide much of the difference between HDR and SDR. It doesn’t take much light to do that, so to get the full visual benefit, you’ll want the viewing space as close to a black hole as possible.