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Discussion Starter · #1 ·
i have masking made of back velvet floor to ceiling, and a couple feet on each side.

i generally position the pj for constant height/variable width, so the black velvet borders the live picture area and sets it off pretty sharpley.

lately i've noticed, during darker scenes i can percieve a light area where the bottom letterbox bar would be.

its not percievable during bright scenes.

i can't for the life of me figure out why it would be lighter.

for one thing, this is area that would be projecting black (or at least very dark grey) since it is letterbox border area,

and secondly the velvet really does a pretty good job of soaking up light in other areas.


it doesn't seem to be the much discussed light spill.

the light spill i can see, but it is much , much farther away from the live picture area (about 3-4').

the light area i'm seeing borders the bottom of the picture and is about 1/4-1/3 the height of the screen (in the case of 2.35 movies this makes it about 18".


it's starting to drive me nuts.
 

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Does it happen with every movie and every source (Svideo, VGA, component) or just with certain ones? Does shutting it down and unplugging it (cold reset) helps? Do you use HTPC as Powerstrip can put in white pixels now and then? Is it related to how long the PJ is running (how hot it get)? Is your PJ ceiling or table mounted with or without hushbox as ceiling hushbox has more heat? Could it be a huge dust blob especially if it's on the DMD like a hair? Have you tried to clean the optical assembly with compressed air? Do you use an optical filter as it could be back reflection onto the DMD? Are they a whole row of stuck pixels, if so a cold reset should fix it? Otherwise, I'd call tech. support for Instacare action :D
 

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Discussion Starter · #3 ·
Hi Huey,

out of the scenarios you describe, reflection off the hoya filter i'm using seems the most plausible.

it seems like i may have first noticed as i started using the filter, but i can't be sure.

i'll have to check that next time.


usage is 100% consistent : component - rgb, always a cold start (its unplugged/disconected and shelved after every use), it sits on a cart i made, no hushbox, no htpc).
 

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I see the same exact thing on my LT150Z. I have a full velvet wall like yourself and on darker seens the 4:3 lettbox can be slightly seen. On brighter seens you cant notice it at all. I hvae my Lt150z set so the picture goes to the top of the 4:3 area so all my halo / lightspill is down below.



Mac
 

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I angled my Hoya HMC filter slightly to reflect the light away from the DMD and down towards the light trap inside or even on the floor outside the PJ. I realized there is slightly more reflection due to angle of incidence is greater but it's worth the very, very slight light loss (not noticeable) to gain the contrast that's loss from back lighting the DMD.
 
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