4% light decay at 800 hours......twice?
How is this possible?
I measure with a high quality light meter after almost every viewing session, plus verified periodically with a colorimeter.
At high bulb, open iris I was getting about 1550 lumens new, and am getting about 1200 lumens now in the same config.
This is with the original lamp.
How are you measuring?
What is your foot candles, how wide is your screen, and are you using a lens / anamorphic mode, or aspect zoom mode?
Yeah I don't see how 4% is possible at 800 hours, low lamp usage or not.
I use a lux meter and take a single measurement at the center of the screen which is 100" diagonal. I don't use an anamorphic lens/mode or aspect zoom etc. The day that I installed the lamp the lux reading was 440 (roughly 1200 lumens). I generally measure every 100 hours. This morning's lux reading was 420 (roughly 1157 lumens). I take all readings in low lamp with a 100 % gray field test pattern, Iris wide open.