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I'm no expert on this subject, but there are at least two main effects when backlighting is done properly.


First, the backlight should cause your iris to "f-stop" down (constrict) more, thereby improving apparent black level in the image.


Secondly, prpoer backlighting entails the use of a 6500K light source. This color temp should improve apparent contrast (?) and relative color balance in the image.
 

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Discussion Starter · #3 ·
I'll look more up on the key ideas you gave me.


Does anyone have designs of proper backlighting and how to do it if your screen is flat against a wall with masking around the screen a curtain around that? How would you "backlight" this instance? Or would it be more of a "side" light?
 

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My one huge problem with bias lighting of any kind..is that it is strictly a band-aid solution. It is there it make up for projection deficencies. I'd rather fix the PJ, or move on to a new one.
 

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Discussion Starter · #7 ·
Quote:
Originally posted by KBK
My one huge problem with bias lighting of any kind..is that it is strictly a band-aid solution. It is there it make up for projection deficencies. I'd rather fix the PJ, or move on to a new one.
Read the thread Rgb talks about above... It makes alot of sense and I think alot of people have come to conclusions...
 

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"and rich looking, if the projector has limited darkness of black."


Unquote.


First paragraph. i'm not railing about trying to get your particular Pj to give you a better image, jsut ... better PJ's are what's required..as a fact....FIRST.
 

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Unlike many of the voodoo audio tweaks (green pens, magic pyramid crystals that sit on top of amps or transports, etc), bias lighting can provide bonafide results that are easily repeatable and provable.


Ever take a photo of something/someone with a bright light behind them (interior photo in front of a window in daylight) with auto exposure "on" and no flash? You'll probably end up with the subject being very dark and maybe so dark as to see no detail in the subject.


Adjust the lighting behind the subject downwards, and the camera's exposure and f-stop (your iris) gradually, and you will reach a point of optimum backlight, f-stop, and exposure settings that optimizes the subject's (your screen in a HT) image- detail, contrast, etc.


You eyes will adjust f-stop and exposure for you- you just need to adjust the bias lighting.
 

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Discussion Starter · #10 ·
Rgb, I don't think I've seen it put as clearly anywhere else.


I know movie theaters don't use back lighting because the screen takes up the whole front wall, but they do have sconces, dim overhead can lights... and rope light along the floor. This gives enough ambient light to keep your pupil/iris from freaking out on bright and dark scenes.


In a HT, back lighting will accomplish this best due to any other light spilling on to the screen and washing the picture away. Its not as noticible in a movie theater due to the large space between lights and the screen itself.
 
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