Foot Lambert Calculations for 2.35 Screen - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 08-11-11, 12:04 AM
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Re: Foot Lambert Calculations for 2.35 Screen

No doubt - but if you're screen shopping, it helps to do the math to make sure you're at least in the ballpark. It won't ever be 100% correct due to variations in individual projectors and bulb aging, etc. - but better than nothing.

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Old 08-11-11, 09:55 AM Thread Starter
Shackster

Join Date: Jan 2011
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Re: Foot Lambert Calculations for 2.35 Screen

I measured about 13 foot candles projecting a 143" Diagonal 16:9 image using the meter. This is actually close to what I calculated.

The question becomes how long I can expect to have sufficient brightness over the bulb life. I was considering doing a painted DIY screen, but I'm wondering if I need to get a screen with higher gain such as the Carada Brilliant White or even the Da Lite High Power.
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Old 08-11-11, 11:11 AM
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Don

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Re: Foot Lambert Calculations for 2.35 Screen

Quote:
jhan1000 wrote: View Post
I measured about 13 foot candles projecting a 143" Diagonal 16:9 image using the meter. This is actually close to what I calculated.

The question becomes how long I can expect to have sufficient brightness over the bulb life. I was considering doing a painted DIY screen, but I'm wondering if I need to get a screen with higher gain such as the Carada Brilliant White or even the Da Lite High Power.
I can't give you hard facts about lamp brightness over their lifetimes since I have never seen any; all I know is what is generally stated about lamp life on the forums which is that a lamp will dim about 50% over it's life, but that is not linear and most of the dimming occurs within the first half of it's life expectancy. With your meter you can keep tabs on this. I wish every PJ came with a meter; if that were so we would actually have hard numbers to quote by now.

Depending on what mode you use the PJ in at the beginning you could increase brightness if needed by changing from eco mode to full lamp or to a brighter projection mode rather than put up with the disadvantages of a higher gain screen; but this is all subjective and totally up to the theater owner.

If I remember my facts right, for the "average" HT owner one screen will usually out live two or three PJ's so I personally would hesitate compromising the viewing angle and color richness of my image by going with too high a gain screen. But that's just me.
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