Backlit Screen - Huge Black level improvement. Full Fade To Black Video Inside!!!

I've mentioned my back lit screen on the CRT forum a few times, but only now have I been able to demonstrate the difference in black level with my Optoma H79 on my super high gain curved silver screen with the back light on vs off.

The animated gif video below starts off with a full fade to black at 9'2" diagonal and after a few seconds you will see the back light come on and see how much darker the absolute black looks.



Just thought I'd share now that I'm able to. Any opinions or comments?

Obviously it doesn't reduce light output. It's perception, but perception can be everything...it is very real though. The human eyes are equipped with our very own dynamic irises just like the current crop of LCD projectors, only far more advanced. If you have ever come in from a bright sunny day to a much dimmer room take note of how dim the room is before you eyes adjust. Usually your irises act so fast you can barely tell you have them, but in extreme cases your eyes adjust slower and you can tell if you take notice.

During a long very dark scene or fade to black normally your eyes' irises would open up wider and wider allowing more and more light in. The longer the dark scene or fade to black is the brighter the darkest black will appear because your eyes are adjusting more and more. The back lighting forces your irises to close down during these types of scenes/fade to blacks so your eyes will not allow more light in during such dark scenes/fade to blacks....thus you take in less light and see a much darker blacker black.

The effect should actually be better with a blue, green or white light. Red has less of an effect on the irises than those. I'm considering giving blue a try.

I tried the back lighting with a white screen and it simply does not work in a room with white walls. It caused black washout instead and gave a red cast to the image (especially blacks). However, I use a very high gain torus screen and it already rejects ambient light very well, so there is no cast or anything to the image, not even a fade to black. If it lowers the contrast ratio it is to a very minute degree, yet you still perceive many times the contrast due to the black level being many times darker to the eye.

Obviously, but a much greater and real effect on perceived contrast, a much better looking black level and the whole image doesn't look dimmer. Also, you don't have to wear sunglasses with the lights off and look like someone trying to be super cool.

I don't see anything but a black image.

Yeah, that just means your camera has a poor and small sensor, unless you are using a CRT projector, which wouldn't register with any camera or the human eye. lol. The human eye is far more sensitive than either of our cameras when it comes to seeing a fade to black.

BTW, for the record....I had to bump up the brightness about 20-30 points to keep it from recording a solid black image like you did. For the camera to see a fade to black the way my own eyes did at the correct brightness setting I had to bump it up to the point where it was a very bright medium gray. Recording a pitch black image is not reality though, so that is pointless if I took it and said "Look! My fade to black is so dark my camera can't register anything! Wow...that is so black!"......All that means is the camera's sensor sensitivity sucks compared to the human eye's sensitivity. Obviously, that would be a ridiculous test if I showed a totally black image without back lighting that is not representing the reality of what I see compared to with the LED lights being used.

The point here was to show a real world difference, not prove that a camera with a can't see a fade to black at the correct brightness setting because it has a poor sensor compared to the human eye. Both blacks would end up looking near equal except one without lights in the shot. Again, not reality. Not saying you have to use LED lights, but some find tests like this to be interesting.