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Discussion Starter · #1 ·
Hey everyone. First time poster here, but have been lurking for a bit.

I have recently painted a 120" screen for my BenQw1070, roughly 3 weeks ago. Since then I have discovered that it is hotspotting, and its very noticeable during some scenes, especially football games where the grass color should be uniform throughout, but the center of the screen (vertically from top to bottom) is noticeably brighter than the left and right of the screen.

But here is my question. Outside of the screen paint used (I know this is probably the biggest culprit), I suspect I may have two other issues causing this. The first, I am concerned my projector may be the culprit of some of the excessive light. Though the vertical "spot" will move slightly left and right as you walk across the room, so maybe not. Any ideas short of getting a light meter to test what the projector is shooting?

Also, and I fear this may be my biggest problem, When I installed my substrate (sintra) to the wall, I noticed my sheetrock wall had a noticeable bow to it (the center of the screen may be projected a 1/2" farter out than the two sides). I went ahead and attached it to the wall thinking (or not thinking) this wouldn't be a problem. Could having a curved surface, with the center closer to the projector than the sides, cause hotspotting in the center? It certainly makes sense that it would..

So my three culprits in order that I suspect are:
1) screen paint
2) bowed screen
3) projector

Thanks in adavance for any help. My next step may be repainting, but want to eliminate the other two variables first.
 

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A 1/2" bow out is highly unlikely to cause a noticeable brightness change. I think its the paint that is causing this. What paint/sheen did you use?
 

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Hey everyone. First time poster here, but have been lurking for a bit.

I have recently painted a 120" screen for my BenQw1070, roughly 3 weeks ago. Since then I have discovered that it is hotspotting, and its very noticeable during some scenes, especially football games where the grass color should be uniform throughout, but the center of the screen (vertically from top to bottom) is noticeably brighter than the left and right of the screen.
Before give the blame to the paint or your painting skills, check out the light uniformity of your projector. I have already measured 2 and both of them had issues of that kind (nearly 30-35% loss between center and edges). Just a thought...
 

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Discussion Starter · #5 ·
Before give the blame to the paint or your painting skills, check out the light uniformity of your projector. I have already measured 2 and both of them had issues of that kind (nearly 30-35% loss between center and edges). Just a thought...
This has actually become my leading suspect on this. Do you have any advice on how to measure this? I dont have a light meter, etc.. Also when you say you've measured 2, I assume you are referring to W1070's. Would you recommend I contact BenQ on this, or is it just what you get with a sub $1,000 projector?
 

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Please let us know what paint you used.
 

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Discussion Starter · #7 ·
Please let us know what paint you used.
Thanks for your response again.
I was deliberately leaving out the paint used so that the thread would not get sidetracked with that conversation, as there is adequate discussion in these forums about it, and problems others have had with it hotspotting. You probably know what I'm talking about. I wanted to more specifically ask on the uniformity issue of the projector and the curved wall of the sintra.

I think the paint is in fact causing a problem, but I also wanted to explore the possibility that the projector and wall are helping push the hotspotting of the paint further than where it would be otherwise... Was just curious with any experience on those two?
 

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This has actually become my leading suspect on this. Do you have any advice on how to measure this? I dont have a light meter, etc.. Also when you say you've measured 2, I assume you are referring to W1070's. Would you recommend I contact BenQ on this, or is it just what you get with a sub $1,000 projector?
Yes, by 2, i mean two units. I believe it's a shortcoming in the whole line of production caused by the specific type of lamp used. You can contact Benq though if you like.

If you don't have a sensor, i can't quite think of a different way to measure uniformity.
 

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This has actually become my leading suspect on this. Do you have any advice on how to measure this? I dont have a light meter, etc.. Also when you say you've measured 2, I assume you are referring to W1070's. Would you recommend I contact BenQ on this, or is it just what you get with a sub $1,000 projector?
I have zero hotspotting with my BenQ 1070 projecting onto a 134" Jamestown screen. This is the second projector from them (first one had excessive fan noise after 200 hours of use), and neither one had hotspotting. I had hotspotting years ago with a dif brand projector and it was the screen that was causing it. I tend to believe it is your screen too.
 

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As far as the screen being bowed... Would it be possible to shim the screen out in the center? If the bow is causing it it might eliminate the problem, or at the very least take it out of the possible problem.
 

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Discussion Starter · #11 ·
As far as the screen being bowed... Would it be possible to shim the screen out in the center? If the bow is causing it it might eliminate the problem, or at the very least take it out of the possible problem.
To answer your question, yes it would be possible, but not easy. Before I take that step I'm trying to make sure its necessary. As far as uniformity or hotspots with your BenQ, when you put on a solid screen, say like the Ben Q blue background that is an option in the menu without a source, you dont see any variance in the blue projected? It all looks perfectly uniform?
 

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To answer your question, yes it would be possible, but not easy. Before I take that step I'm trying to make sure its necessary. As far as uniformity or hotspots with your BenQ, when you put on a solid screen, say like the Ben Q blue background that is an option in the menu without a source, you dont see any variance in the blue projected? It all looks perfectly uniform?
Yes it looks perfectly uniform (I just switched it to blue and rebooted).
 

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Hi Mark, welcome to HTS! :wave:

I've read most of your original thread over on the other forum and I understand your concern about telling us the screen mix you finally were talked into using, but please know that we won't bash you for believing what others told you; they initially come across as seeming to know what they are talking about. I will tell those participating in this thread that Mark painted his Sintra with the current SF 3.0 formula. And while that is part of his current problem it may have something to do with his PJ too.

Mark, what settings are you using with your PJ? What video mode and what lamp mode? Depending on these you are getting a maximum image brightness anywhere from ~22 fL to ~14 fL.

If you would, please post the photos you have in your other forum thread here as well.

Right now I would have to agree that the slight bowing of your screen probably isn't affecting the hot spotting much, if at all, but your current screen mix would tend to exacerbate any hot spotting problems because of all the uncontrolled mica and it's translucency.

Generally the way to tell if it's the screen mix or the PJ causing hot spotting is this, if the hot spot changes as you move around the room changing your viewing angle it is the screen mix; if changing the viewing angle doesn't cause the hot spot to move then it's probably the PJ. If you have a case where BOTH are causing some hot spotting it could be difficult to tell which one is the predominant cause.

If you want to actually KNOW your PJ's output then I would jump on this deal right now. http://www.amazon.com/Light-Meter-L...F8&qid=1378931090&sr=8-2&keywords=light+meter. This is the light meter we generally recommend and it is downright cheap right now selling for $13.31 and free shipping! I have this meter and it is literally as accurate at reading Lux values as a $450 professional light meter I have.

 

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Discussion Starter · #15 ·
Yes, that is the paint mix used, and I do think it is hotspotting, However I think I have a problem with the projector..
Thank you the link on the meter, Just ordered it from Amazon. For $13 bucks why not own one...

Here are the photos I posted on the other forum. And based on these images, there is a spot that moves with you as you walk through the room, however the right side of the screen is always darker, no matter what angle I view it from... I think I have two different problems going on here.

These are HORRIBLE pictures taken with my phone, and the problem appears 10 times worse in these pics than it does when watching content. But this demonstrates the lack of uniformity.





 

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Hi Mark, welcome to HTS! :wave:

I've read most of your original thread over on the other forum and I understand your concern about telling us the screen mix you finally were talked into using, but please know that we won't bash you for believing what others told you; they initially come across as seeming to know what they are talking about. I will tell those participating in this thread that Mark painted his Sintra with the current SF 3.0 formula. And while that is part of his current problem it may have something to do with his PJ too.

Mark, what settings are you using with your PJ? What video mode and what lamp mode? Depending on these you are getting a maximum image brightness anywhere from ~22 fL to ~14 fL.

If you would, please post the photos you have in your other forum thread here as well.

Right now I would have to agree that the slight bowing of your screen probably isn't affecting the hot spotting much, if at all, but your current screen mix would tend to exacerbate any hot spotting problems because of all the uncontrolled mica and it's translucency.

Generally the way to tell if it's the screen mix or the PJ causing hot spotting is this, if the hot spot changes as you move around the room changing your viewing angle it is the screen mix; if changing the viewing angle doesn't cause the hot spot to move then it's probably the PJ. If you have a case where BOTH are causing some hot spotting it could be difficult to tell which one is the predominant cause.

If you want to actually KNOW your PJ's output then I would jump on this deal right now. http://www.amazon.com/Light-Meter-L...F8&qid=1378931090&sr=8-2&keywords=light+meter. This is the light meter we generally recommend and it is downright cheap right now selling for $13.31 and free shipping! I have this meter and it is literally as accurate at reading Lux values as a $450 professional light meter I have.

Thanks for the link... I just ordered one, but the price was $15.00 (Amazon Prime), which is still a good deal for me as I have been wanting to get one for a while.
 

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Yes, that is the paint mix used, and I do think it is hotspotting, However I think I have a problem with the projector..
Thank you the link on the meter, Just ordered it from Amazon. For $13 bucks why not own one...

Here are the photos I posted on the other forum. And based on these images, there is a spot that moves with you as you walk through the room, however the right side of the screen is always darker, no matter what angle I view it from... I think I have two different problems going on here.

These are HORRIBLE pictures taken with my phone, and the problem appears 10 times worse in these pics than it does when watching content. But this demonstrates the lack of uniformity.





Are you running the factory settings, or did you calibrate it? I am running one of the suggested calibrations currently.
 

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Discussion Starter · #18 ·
Are you running the factory settings, or did you calibrate it? I am running one of the suggested calibrations currently.
I did a "beginners" calibration. Just brightness and contrast / gamma only with some test patterns. So basically no... could a calibration solve the uniformity issue? maybe tone it down, but not sure it would change the uniformity..

Do you have a link to the suggested calibrations you are using? I can try searching later.

Thanks
 

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