Originally Posted by Manni01
Sorry for the misunderstanding
I'll try to post the difference next time I get the meters out to make up for it, although it's been done before, I remember someone had posted a graph showing the evolution of greyscale over a couple of hours, I just can't find it.
Okay, I've done some tests and the results are interesting. It's at the same time much worse and better than I thought. All measurements made from my Discus trained to my i1pro2 in a bat cave, reading off the screen from about two feet (the i1pro2 sits a bit further back when I use it as a reference to match the FOV of the two meters). This is with my rs-45, could be different with your PJ and of course it doesn't mean it will be the same for the new range (or even last year's model as the bulb and power supply were improved), but it should be similar. All the numbers below are dE2000.
Looks like for casual watching 20mn is enough to get to a point where most differences are not visible (dEs go from above 10 for gamut, 8 for greyscale at start-up to less than 3). However, while it looks all fine at 20mn, there is a spike at 25mn so to be sure for calibration or critical viewing I'd recommend 45mn, even if 30mn is probably okay for watching. There is no significant change after 45mn, the results are virtually the same at 60mn as we're only seeing minor bulb variations / meter repeatability issues. I had planned to measure up to 120mn but it was clearly not necessary. It's quite cold here at the moment so I suspect there would be more variations for a longer time in the summer as the heat from the projector would accumulate in the room and cause further drifts as the room temp would shoot up. But if you have a room with a stable temp, 45mn seems to be enough warm-up time before a calibration.
I was expecting the gamut to be affected, but not that much. The errors are in fact higher and it takes a longer time for the gamut to get within a reasonable state than the greyscale. That's another good thing to know.
It also looks like the errors are bigger in the greyscale between 20% and 50% white, so my suggestion of testing the RGB balance at 70% or 100% was not great as it would have shown a much smaller variation (at least on my unit).
I did a dark calibration right after the 60mn measurement to check for meter drift (there was none), and I added the measurements from my last calibration about two weeks ago (I did this calibration after warming-up the rs-45 for at least 60mn, as I always do, but it's nice to know that 45mn is enough). As you can see, provided you warm-up the projector enough before calibrating, the results are remarkably repeatable. Nice to see that my calibration didn't drift at all over two weeks. One last tip, I have a mark for my Discus on the floor, so that I always use it from the exact same spot (on a tripod), aiming at the centre of the screen (the laser guide helps a lot). That way I don't have to train it to my i1pro2 every time I use it, and it's nice to see with this test that it does work very well and that the results are repeatable.
Here goes the detailed screenshots for those who want to have a look at the detailed raw data.
First the results of my last calibration two weeks ago, as this is ideally what we want to get back on screen if we leave enough warm-up time:
Then all the measurements I did today, every 5mn from startup to 30mn, then at 45mn and 60mn. I had forgotten to take a screenshot of the 25mn one, so I did it afterwards. Be ready for a shock as the first few ones are UGLY
And finally my meter check (after a dark recalibration performed right after the last 60mn measurements, to show that the meter had not drifted over the hour it took to take all the measurements).
Hope this helps!Edited by Manni01 - 11/8/13 at 8:37am