Calibration- Possibly the most important thing to read here or anywhere... - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 4 Old 11-02-08, 02:58 AM Thread Starter
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Calibration- Possibly the most important thing to read here or anywhere...

The title says it all, but for anyone new it does need an explanation.

Many times I see people go from one screen to another and express comments about how bad one screen is as compared to another. If the screens are both similar, then it is relevant, but if one is a white screen and the other a gray screen, a comparison this way means very little.

For starters if the screens are totally different in properties then they will perform differently. Calibration though makes a huge difference. If your projector is calibrated for a higher gain white screen then any gray screen, be it commercial or DIY will suffer by comparison. Conversely if you are calibrated to the gray screen, then the white screen suffers.

Here is a perfect demonstration of that. Recently I have been going through all the threads to clean things up and archive any really good information and this comparison really stood out. I have talked about this topic many times, but this illustrates it better than anything I have seen.

This applies to both commercial screens as well as DIY options. I think the best way to demonstrate this though is with commercial screens. That way it removes any of the hype and sometimes bias that comes with DIY.

Here we see a comparison between a Da-Lite High Power screen and a Da-Lite Silver Matte. The Silver Matte is very dark and a much lower gain screen, whereas the High Power is very white and well over double the gain.

At an initial glance, the HP totally blows away the Silver Matte as can be seen in this shot.

Let's look at this and talk about it for a minute. Nobody can deny the HP mops the floor with the much darker Silver Matte. Just look at it! How could anyone want a darker screen? It is bright, vibrant, and much more accurate at reproducing the projected colors.

That's a bit misleading though. This is where calibration comes in. That shot was calibrated to the HP. Any time a projector is calibrated to one particular screen of course that screen is going to look its best.

What happens though if we recalibrate? This is often overlooked and for a novice who doesn't understand this concept, they can easily be led to believe one screen is far superior than another.

Let's look at what happens after a recalibration to the darker screen.

Now the tables turn. The difference isn't nearly as dramatic as in the first comparison. Still it can be said that the HP looks better with a slightly brighter image and more vivid colors. However the Silver Matte has much better blacks and it is holding its on against the HP.

For a totally dedicated HT setup that also has total light control- and this also depends on your projector and how good the CR rating is as well as its ability to produce true blacks... a white screen rules. However more and more people are integrating projectors into family rooms and multi-purpose living rooms where light control is less than optimal or there is a desire to watch the big screen with some lights on. One scenario that comes to mind is a Super Bowl party. Nobody wants to watch the big game with all the lights out. It's a party atmosphere and completely different than a movie theater setting.

Also TV comes to mind. I personally don't use my projector for TV shows, but many people do. This is a very common environment where there is the potential for some lights to be on in the room.

A white screen will not perform as well in this type of setup- period.

There are many myths with screens, especially when it comes to DIY screens. I specifically used commercial screens here to show this isn't just a DIY dilemma, but does matter even with commercial screens. Calibration is the difference between a good image and one that blows your socks off. It also could change a person's mind between two totally different types of screens.

Always calibrate to your current screen, and always recalibrate any time you change screens. Even more important... when comparing two very different types of screens always calibrate to each screen before making a final decision. I know many people that have dedicated theaters that prefer a gray screen to a white screen. It all boils down to some basic variables- What can your projector do? In order to know this you need to do a baseline calibration to a unity gain white screen. Next is what is your viewing environment like? And last, what is your personal preference and tastes?

Do not let anyone tell you what screen is best for you and blindly accept it. Do the research and comparisons. If you are spending the time and money to build a Home Theater room or a multi-purpose room, then spend just a little extra time to do a basic calibration to see how different screens perform.

If you don't have a calibration disc like Avia or DVE then use the THX Optimizer found on all THX certified DVD. The difference really will amaze you.

"Make everything as simple as possible, but no simpler." - Albert Einstein

"If all else fails, spin the cat."- Grzboken
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post #2 of 4 Old 11-02-08, 03:27 AM
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Re: Calibration- Possibly the most important thing to read here or anywhere...

Great post, Bill. The difference really is drastic.

Another time folks might want to recheck their calibration is when they install a new lamp, or after a couple of hundred hours on a new lamp. I know I needed to make some changes when I installed a new lamp to keep the old one for a backup. The new only has about 80 hours on it now, so still settling in, I'll check it again sometime after 200 hours.
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post #3 of 4 Old 11-02-08, 04:13 AM Thread Starter
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Re: Calibration- Possibly the most important thing to read here or anywhere...

Good point Chris.

Anytime anything major changes in your setup, a recalibration should be done. Changing bulbs definitely should have a new calibation done.

The break in period of a bulb is around the 200 hour mark. Everyone can expect their image brightness to drop at least 10% but from there on out it should remain relatively consistant until it starts getting towards end of bulb life.

Projectors definitely need to be calibrated and recalibration throughout the bulb life, although it may seem like a pain, is part of the price of having that huge screen everyone drools over!

"Make everything as simple as possible, but no simpler." - Albert Einstein

"If all else fails, spin the cat."- Grzboken
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post #4 of 4 Old 05-10-09, 09:43 PM
 
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Re: Calibration- Possibly the most important thing to read here or anywhere...

Very nice informaiton. Thanks!
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