Originally Posted by millerwill
I appreciate your point. It depends on the size of the screen one has/wants. Below a certain level of brightness the pic just looks dull, no matter what else.
But how come is it that in comparing projectors, everyone is adamant about making sure that they are 'brightness matched''; it's because the brighter projector will always be perceived as 'better', more dynamic. If it's better, for whatever reason, isn't better 'better'?
Because it all depends on what you're trying to compare, and why you're trying to do it. The biggest, or maybe simplest to understand, reason you want two projectors brightness matched is because as Darin says, our perception is all relative. Take white for example, what we perceive as "white" is absolutely relative. I'm looking at my LCD screen typing this in a white text box. It's white because it's the brightest thing in my current field of view. If I took this screen out in the sun, didn't change anything, that "white" would appear gray because there would be brighter things in my field of view.
If one projector is brighter than the other, than necessarily one will appear to be able to produce white, while the other won't. It's just a fact of how we perceive things.
If you don't brightness match the two projectors it will skew all sorts of things, relatively
between the two, contrast perception, color perception, and of course the ability to produce white. So if you're comparing two projectors, especially if your goal is to do a writeup, to report to others, you have to brightness match them to accurately evaluate how they handle color, contrast, etc.
that you throw brightness into the mix, because that is more of a "tool" than a measure of quality. What I mean is brightness isn't a quality in and of itself, and it's the one thing you have control over when you design a home theater system. You can use a screen with more gain, that's a smaller size, etc, to adjust for projector brightness. Or, if you've just got a big screen, you'll know you need a lot of brightness and to go with the brighter projector.
Lastly, if you're "just" comparing for yourself, in your own theater, of course you don't ignore brightness, nobody is say you should. I would recommend you brightness match first to get a sense of the relative attributes of both projectors, but of course, if in your theater you find brighter to be better, then absolutely consider that, you'd be silly not to.