Solution for hot-spotting - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 8 Old 06-26-2020, 05:52 AM - Thread Starter
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Question Solution for hot-spotting

I can't post links or images yet so this will make it more difficult...



I bought a Euroscreens ReAct 3.0 tab tension screen and which has gain 1.0 and a viewing angle of 76 degrees.
I noticed that the edges of the screen was darker then the center, which I found very annoying. I talked to the place I bought it and they simply said it was hot-spotting and refused to do anything.
My viewing position is in the center of the screen and if I move my position so I sit in a straight line from the left side of the screen then that side looks good (brighter than before).

My projector is a Sony VW270ES (know as a Sony 295ES in the US).
The screen is 118" 16:9.
The distance from the projector to the screen is about 4 meters (13 feet).
I almost use full zoom on the projector to get the 118" picture in that distance.
According to the projector screen info the distance should not be a problem (2x the image height).

I talked to the manufacturer and they agreed to change the screen for another with another material: Euroscreens FlexGrey with a gain of 0.8 and a viewing angle of 180 degrees.

I'm trying to make sure what my problem is exactly. Is it 100% a hot-spotting problem?
I would hate to change the screen and still have a problem.
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post #2 of 8 Old 06-26-2020, 05:54 AM - Thread Starter
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It seems that I could include a photo after all....


There are 3 images taken from different angles of the screen with ReAct 3 material.
To the left is a test-piece (A4-size) of the new material (FlexGrey).

From the left side (top picture) the difference is minor.
From the middle (normal viewing position) there is a big difference.
My phone-camera does, of course, not capture the colors etc perfectly but the difference in lighting is shown in a good way.
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post #3 of 8 Old 06-26-2020, 06:01 AM
 
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Quote:
Originally Posted by AnAx View Post
I can't post links or images yet so this will make it more difficult...



I bought a Euroscreens ReAct 3.0 tab tension screen and which has gain 1.0 and a viewing angle of 76 degrees.
I noticed that the edges of the screen was darker then the center, which I found very annoying. I talked to the place I bought it and they simply said it was hot-spotting and refused to do anything.
My viewing position is in the center of the screen and if I move my position so I sit in a straight line from the left side of the screen then that side looks good (brighter than before).

My projector is a Sony VW270ES (know as a Sony 295ES in the US).
The screen is 118" 16:9.
The distance from the projector to the screen is about 4 meters (13 feet).
I almost use full zoom on the projector to get the 118" picture in that distance.
According to the projector screen info the distance should not be a problem (2x the image height).

I talked to the manufacturer and they agreed to change the screen for another with another material: Euroscreens FlexGrey with a gain of 0.8 and a viewing angle of 180 degrees.

I'm trying to make sure what my problem is exactly. Is it 100% a hot-spotting problem?
I would hate to change the screen and still have a problem.
Put up a picture of the same image from a television so we also have a reference from a non screen surface. I would try watching the same content and other test scenes on a television to rule out any artifacts in the source material.

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post #4 of 8 Old 06-26-2020, 06:09 AM - Thread Starter
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Quote:
Originally Posted by skylarlove1999 View Post
Put up a picture of the same image from a television so we also have a reference from a non screen surface. I would try watching the same content and other test scenes on a television to rule out any artifacts in the source material.

I'll try to get a photo of the same image from my LG OLED TV later when I get home, but I'm pretty sure it's not a source material problem since I have noticed this problem with mostly all content I have watched on the screen but I have zero problems with my old projector and screen and never had the problem on different TV's.


To summarize: The problem is with all content (movies) but less noticeable in some. I have never had this problem before (multiple TV's and 1 projector/screen).
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post #5 of 8 Old 06-26-2020, 06:52 AM
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Quote:
Originally Posted by AnAx View Post
I can't post links or images yet so this will make it more difficult...



I bought a Euroscreens ReAct 3.0 tab tension screen and which has gain 1.0 and a viewing angle of 76 degrees.
I noticed that the edges of the screen was darker then the center, which I found very annoying. I talked to the place I bought it and they simply said it was hot-spotting and refused to do anything.
My viewing position is in the center of the screen and if I move my position so I sit in a straight line from the left side of the screen then that side looks good (brighter than before).

My projector is a Sony VW270ES (know as a Sony 295ES in the US).
The screen is 118" 16:9.
The distance from the projector to the screen is about 4 meters (13 feet).
I almost use full zoom on the projector to get the 118" picture in that distance.
According to the projector screen info the distance should not be a problem (2x the image height).

I talked to the manufacturer and they agreed to change the screen for another with another material: Euroscreens FlexGrey with a gain of 0.8 and a viewing angle of 180 degrees.

I'm trying to make sure what my problem is exactly. Is it 100% a hot-spotting problem?
I would hate to change the screen and still have a problem.
So many things to unpack here.




Take a picture of the entire screen while projecting an 100% white image.


I've talked to other users about this. I don't don't why the website says it's 2x the image height, it should be 1.9x/2.0x the image width.

With an 118" (16:9) screen the width is 102.8" or 8.56'.
So 1.9x is 16.2' and 2.0x is 17.12‬'.

From 13' (156") is 1.51x throw ratio. So this is why there's a hotspot. The projector should be placed on the screen's central axis, perpendicular to the screen, but I assume it's installed this way (?).



ALR screens work like a mirror. If the projector is too close the light from the projector will bounce off the screen and go towards the viewer's position. But this is only for the center of the screen. The light that goes towards the edges (if the projector is too close) will end up on the walls because the angle is too high. The further back the projector is, the lower the angles will be and the reflection will be sent back closer to the viewer.

If you move your head left to right, you'll notice that the hotspot follows your vision. That's because of the mirror like aspect of the screen. A matte surface send light in all directs equally, while with an ALR screen you see the light that hits your eyes at the actual brightness, with the light outside your vision being less bright since the screen is directing it further away.



But why did you choose an ALR screen?

What is the room like, color of walls?


Thirdly is the choice of projector. Unless you got a fabulous deal on the Sony, a JVC NX5/RS1000 would have been a much better choice.
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Last edited by noob00224; 06-26-2020 at 06:56 AM.
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post #6 of 8 Old 06-26-2020, 06:59 AM
 
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Quote:
Originally Posted by noob00224 View Post
So many things to unpack here.




Take a picture of the entire screen while projecting an 100% white image.


I've talked to other users about this. I don't don't why the website says it's 2x the image height, it should be 1.9x/2.0x the image width.

With an 118" (16:9) screen the width is 102.8" or 8.56'.
So 1.9x is 16.2' and 2.0x is 17.12‬'.

From 13' (156") is 1.51x throw ratio. So this is why there's a hotspot. The projector should be placed on the screen's central axis, perpendicular to the screen, but I assume it's installed this way (?).



ALR screens work like a mirror. If the projector is too close the light from the projector will bounce off the screen and go towards the viewer's position. But this is only for the center of the screen. The light that goes towards the edges (if the projector is too close) will end up on the walls because the angle is too high. The further back the projector is, the lower the angles will be and the reflection will be sent back closer to the viewer.

If you move your head left to right, you'll notice that the hotspot follows your vision. That's because of the mirror like aspect of the screen. A matte surface send light in all directs equally, while with an ALR screen you see the light that hits your eyes at the actual brightness, with the light outside your vision being less bright since the screen is directing it further away.



But why did you choose an ALR screen?

What is the room like, color of walls?


Thirdly is the choice of projector. Unless you got a fabulous deal on the Sony, a JVC NX5/RS1000 would have been a much better choice.
I agree with everything posted here. The one thing we do not know if how much JVC costs in his country. Sony is lower priced in some countries and JVC significantly higher and vice versa. JVC would have been the clear choice if prices were equal but that may not have been the case.

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post #7 of 8 Old 06-26-2020, 07:18 AM - Thread Starter
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Quote:
Originally Posted by noob00224 View Post
So many things to unpack here.

Take a picture of the entire screen while projecting an 100% white image.


I've talked to other users about this. I don't don't why the website says it's 2x the image height, it should be 1.9x/2.0x the image width.

With an 118" (16:9) screen the width is 102.8" or 8.56'.
So 1.9x is 16.2' and 2.0x is 17.12‬'.

From 13' (156") is 1.51x throw ratio. So this is why there's a hotspot. The projector should be placed on the screen's central axis, perpendicular to the screen, but I assume it's installed this way (?).



ALR screens work like a mirror. If the projector is too close the light from the projector will bounce off the screen and go towards the viewer's position. But this is only for the center of the screen. The light that goes towards the edges (if the projector is too close) will end up on the walls because the angle is too high. The further back the projector is, the lower the angles will be and the reflection will be sent back closer to the viewer.

If you move your head left to right, you'll notice that the hotspot follows your vision. That's because of the mirror like aspect of the screen. A matte surface send light in all directs equally, while with an ALR screen you see the light that hits your eyes at the actual brightness, with the light outside your vision being less bright since the screen is directing it further away.



But why did you choose an ALR screen?

What is the room like, color of walls?


Thirdly is the choice of projector. Unless you got a fabulous deal on the Sony, a JVC NX5/RS1000 would have been a much better choice.

Thanks for the info.


I have removed the screen so I can't take any new photos of it.



I choose the screen because it was recommended by the store and also because it had good reviews. That it was an ALR screen or not was outside of my knowledge.
I researched this quite a bit before buying but strangely enough didn't I see anything about hot-spotting. I didn't even know about it until I got my problem and looked into it.


The projector is places in the ceiling perpendicular to the screen. The mount might lower it about 30 cm from the ceiling (12 inches).


If I understand you correctly then you are saying that the projector was to close to the ALR screen and that's why I see the hotspot?
What can I then do in my situation? Will the other screen (FlexGrey) fix the problem (I'm unsure if that's also an ALR screen?).
The projector is in the back of the room so I can't move it back any more.


I talked to the shop where I bought both the projector and the screen, at the same time, about my room-situation and also exactly about that it would not cause a problem with the placing of the projector and the (almost) max zoom.

When I later returned to the shop with my issue they simply said it's a hot-spot issue and some people notice it and others don't so they did no error - which I believed so I started talking to the screen manufacturer instead.


I didn't buy the JVC because it was around 20% more expensive, if I remember correctly, and I didn't see the point.
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post #8 of 8 Old 06-26-2020, 08:08 AM
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Thanks for the info.


I have removed the screen so I can't take any new photos of it.



I choose the screen because it was recommended by the store and also because it had good reviews. That it was an ALR screen or not was outside of my knowledge.
I researched this quite a bit before buying but strangely enough didn't I see anything about hot-spotting. I didn't even know about it until I got my problem and looked into it.


The projector is places in the ceiling perpendicular to the screen. The mount might lower it about 30 cm from the ceiling (12 inches).


If I understand you correctly then you are saying that the projector was to close to the ALR screen and that's why I see the hotspot?
What can I then do in my situation? Will the other screen (FlexGrey) fix the problem (I'm unsure if that's also an ALR screen?).
The projector is in the back of the room so I can't move it back any more.


I talked to the shop where I bought both the projector and the screen, at the same time, about my room-situation and also exactly about that it would not cause a problem with the placing of the projector and the (almost) max zoom.

When I later returned to the shop with my issue they simply said it's a hot-spot issue and some people notice it and others don't so they did no error - which I believed so I started talking to the screen manufacturer instead.


I didn't buy the JVC because it was around 20% more expensive, if I remember correctly, and I didn't see the point.
Yes the hotspot is being caused because the projector is too close. In this case there's nothing you can do with an ALR screen of that size in that room.

The grey screen seems to be a matte surface:
https://www.euroscreens.se/home-3/pr...2.aspx?pid=919



I still don't know why you were recommended an ALR screen.

Usually ALR or grey screens are for untreated rooms, to help with room reflections or even some ambient light. However with that projector the room should be treated and a white screen used.

Here's what an untreated room does to black level/contrast:
https://www.facebook.com/projectiond...2721894385217/

While ALR screens are somewhat effective at fighting ambient light, the best way to deal with this is by treating the room. The area closest to the screen, ~5', would benefit the image the most. This includes the ceiling, screen wall, and floor (dark rug).

There's a thread on room treatment here:
https://www.avsforum.com/forum/24-di...image-256.html

Grey screens are much less effective at fighting ambient light than ALR screens.

There is another solution, that's paints with ALR properties. The paint mix can be customized and fitted to your setup so no hotspot. However the less artifacting (hotspots), the less light rejection properties the screen has. Paints can be applied on a cheap white screen or a smooth white wall.
There's an argument that a paint mix would be beneficial even in a treated room since the Sony is not the best when it comes to black levels.

There are some ALR screens which artifact less or very little at 1.5x throw ratio, but they are north of $4000, and the side rejection capability is not good.




All of this being said, you should not pick a screen until you've used the projector for a while on the wall. General ratios are general, but from what I assume a viewing distance of 350cm, an 118" screen is rather small.
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