HIGH POWER a Review! Part 1 - Page 119 - AVS Forum
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post #3541 of 3787 Old 05-12-2011, 07:20 PM
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Quote:
Originally Posted by Hughman View Post
A white screen effects on light bouncing around a room is similar to a racquet ball, a gray screen more akin to a squash ball.
A gray screen turns the projector into a squash ball too. Just sayin'. This has been debated endlessly elsewhere. But I do believe a directional screen like the HP can help a lot. But gray just cuts everything equally. But what the heck do I know? Da-Lite seems to be making the stuff!
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post #3542 of 3787 Old 05-12-2011, 08:12 PM
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Quote:
Originally Posted by erkq View Post
A gray screen turns the projector into a squash ball too. Just sayin'. This has been debated endlessly elsewhere. But I do believe a directional screen like the HP can help a lot. But gray just cuts everything equally.
Gray screens tend to be used to achieve two things:

1. Lowering of black levels. They do this, obviously, but just dimming the entire image vs a white screen, so you are lowering the bright parts too.
With consumer digital projectors having much higher contrast/lower black levels these days, (as well as not being terribly bright) most people feel gray screens are no longer necessary for this purpose.

2. Preserving better contrast than a white screen, in more challenging room conditions (e.g. some ambient light and/or reflective room). If you could project an image on to two screens in the same room, and have the image the same brightness on each (for the gray screen you'd open up the iris in order to get more light on the screen, on a projector that can do so)...then the gray screen is going to preserve contrast better.

That is because while you still would have the same brightness of image as the white screen, any other light reflected back to the screen in the room will be dimmed more by the gray screen than the white screen. Hence shadows and dark areas of the image will be less washed out, retaining better contrast.

So...they do indeed work to preserve contrast, when used to do so.
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post #3543 of 3787 Old 05-12-2011, 08:12 PM
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Quote:
Originally Posted by erkq View Post
A gray screen turns the projector into a squash ball too. Just sayin'. This has been debated endlessly elsewhere. But I do believe a directional screen like the HP can help a lot. But gray just cuts everything equally. But what the heck do I know? Da-Lite seems to be making the stuff!
Think about the 2nd reflection then the third and fourth, a screen of less gain kills them quicker. Lets say we have one screen with a gain of .9 and another with a gain of .5 and we increase lumens to maintain equal screen brightness on the .5 gain screen, lets' see how each potentially kills off reflections bouncing around the room.

(.5 screen).... (.9 screen)
360 lumens.... 200 lumens

180...............180
90.................162
45.................146
22.5...............131

What exactly was everyone debating in that thread. Only on AVS could this be debated endlessly. The racquetball vs squash ball analogy is a decent representation, even if you drive a squash ball harder to equal the speed of a racquetball off the first wall, the ball will still die much quicker after that.
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post #3544 of 3787 Old 05-12-2011, 08:12 PM
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Quote:
Originally Posted by erkq View Post
A gray screen turns the projector into a squash ball too. Just sayin'. This has been debated endlessly elsewhere. But I do believe a directional screen like the HP can help a lot. But gray just cuts everything equally. But what the heck do I know? Da-Lite seems to be making the stuff!
A gray screen with 2.4 gain is amazing. Will really look forward to hearing from some knowledgeable people how well it performs.
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post #3545 of 3787 Old 05-12-2011, 08:20 PM
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Quote:
Originally Posted by R Harkness View Post
Gray screens tend to be used to achieve two things:

1. Lowering of black levels. They do this, obviously, but just dimming the entire image vs a white screen, so you are lowering the bright parts too.
With consumer digital projectors having much higher contrast/lower black levels these days, (as well as not being terribly bright) most people feel gray screens are no longer necessary for this purpose.

2. Preserving better contrast than a white screen, in more challenging room conditions (e.g. some ambient light and/or reflective room). If you could project an image on to two screens in the same room, and have the image the same brightness on each (for the gray screen you'd open up the iris in order to get more light on the screen, on a projector that can do so)...then the gray screen is going to preserve contrast better.

That is because while you still would have the same brightness of image as the white screen, any other light reflected back to the screen in the room will be dimmed more by the gray screen than the white screen. Hence shadows and dark areas of the image will be less washed out, retaining better contrast.

So...they do indeed work to preserve contrast, when used to do so.
But if the white HP and gray HP both have gain 2.4, won't they both produce the same brightness (ftL) coming off the screen?
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post #3546 of 3787 Old 05-12-2011, 08:34 PM
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This new gray HP screen really is one of the more exciting things to happen wrt screens in quite a while.

Where are you, Tryg?
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post #3547 of 3787 Old 05-12-2011, 08:50 PM
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Quote:
Originally Posted by millerwill View Post

This new gray HP screen really is one of the more exciting things to happen wrt screens in quite a while.

Where are you, Tryg?

Why do you need Tryg, his viewing it won't change how it performs. Order a sample and see how it works for you.
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post #3548 of 3787 Old 05-12-2011, 09:21 PM
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Quote:
Originally Posted by Hughman View Post

Why do you need Tryg, his viewing it won't change how it performs. Order a sample and see how it works for you.

I have the 2.8, sent the 2.4 back when it was sent to me as 2.8.... If we had a new pro style review for the current screen things for new buyers would be less confusing than reading this thread and finding out they can not buy what was reviewed..
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post #3549 of 3787 Old 05-12-2011, 09:51 PM
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post #3550 of 3787 Old 05-12-2011, 09:51 PM
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The material is available immediately on Da-Lite’s electric, manual and fixed frame screen lines.
nice!
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post #3551 of 3787 Old 05-12-2011, 09:55 PM
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anyone got a price quote?
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post #3552 of 3787 Old 05-12-2011, 10:22 PM
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Quote:
Originally Posted by Hughman View Post

Why do you need Tryg, his viewing it won't change how it performs. Order a sample and see how it works for you.

Only because of his experience. If I do get a new screen (a larger one, to replace my 100x62 2.8HP), will certainly do as you say and order some samples to see how they look.
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post #3553 of 3787 Old 05-12-2011, 10:31 PM
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Quote:
Originally Posted by Hughman View Post

Think about the 2nd reflection then the third and fourth, a screen of less gain kills them quicker. Lets say we have one screen with a gain of .9 and another with a gain of .5 and we increase lumens to maintain equal screen brightness on the .5 gain screen, lets' see how each potentially kills off reflections bouncing around the room.

(.5 screen).... (.9 screen)
360 lumens.... 200 lumens

180...............180
90.................162
45.................146
22.5...............131

What exactly was everyone debating in that thread. Only on AVS could this be debated endlessly. The racquetball vs squash ball analogy is a decent representation, even if you drive a squash ball harder to equal the speed of a racquetball off the first wall, the ball will still die much quicker after that.

Thank you all for your constructive responses.

The debate centered around whether a passive screen could have a non-linear response to lumen level. But this is a different and intriguing scenario. I've been crunching numbers a bit and it seems the benefit happens in the FIRST reflection. It seems a less than unity screen in effect boosts the room's ANSI cr performance.

Say a room's ANSI performance is 400:1 (a figure I've heard thrown around). A .5 gain screen will give an effective room performance of 800:1 and a .9 gain screen will result in a 444:1 performance. Yes, 800:1 is better! It does take projector power, but that is available.
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post #3554 of 3787 Old 05-12-2011, 10:31 PM
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Quote:
Originally Posted by millerwill View Post

But if the white HP and gray HP both have gain 2.4, won't they both produce the same brightness (ftL) coming off the screen?

Yes, essentially. But when erkq said a gray screen just "cuts everything equally" that implied he was talking about gray screens in general. And gray screens can help preserve contrast over a white screen.

Keep in mind that if both the Da Lite gray and white screen end up with the same gain, the gray screen is going to need more optical gain applied to make it as bright. Typically the more gain applied to a screen substrate the more likely you are to see it's effects in the picture - sparklies/specklies etc.

Though Da Lite seems to have come up with a very nice coating for their HP screen. Hopefully screen texture will remain subtle even if they have to put more on the gray screen.
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post #3555 of 3787 Old 05-12-2011, 10:48 PM - Thread Starter
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Quote:
Originally Posted by millerwill View Post

This new gray HP screen really is one of the more exciting things to happen wrt screens in quite a while.

Where are you, Tryg?


I saw the post that they now have a gray screen. Lets see how the response goes then in the fall I'll probably contact da-lite to work something up. It's been five years...maybe it's time to whip something new up
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post #3556 of 3787 Old 05-12-2011, 11:19 PM
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Quote:
Originally Posted by R Harkness View Post

Yes, essentially. But when erkq said a gray screen just "cuts everything equally" that implied he was talking about gray screens in general. And gray screens can help preserve contrast over a white screen.

Keep in mind that if both the Da Lite gray and white screen end up with the same gain, the gray screen is going to need more optical gain applied to make it as bright. Typically the more gain applied to a screen substrate the more likely you are to see it's effects in the picture - sparklies/specklies etc.

Though Da Lite seems to have come up with a very nice coating for their HP screen. Hopefully screen texture will remain subtle even if they have to put more on the gray screen.

Yes, this is a concern: if the HC HP has the same gain as the white HP, then the optical coating must be generating more gain for the HC than for the white screen and thus has a greater chance of giving artifacts (hotspotting, etc.)

Another concern is that Dalite quotes the viewing angle as 20 deg for the HC HP and 30 deg for the white HP. I thought they quoted 30 deg for the old 2.8 HP, but am not sure. But is does seem that the new HC HP has an even narrower viewing cone.

And finally if the gains of the HC and white HP screens are the same, isn't their white level and black level the same? and thus their CR the same? The only difference would thus be in wall reflections, less for the HC because of its narrower viewing cone.
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post #3557 of 3787 Old 05-13-2011, 01:14 AM
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Millerwill,

The HP doesn't hotspot due to its retroreflective nature. Though I imagine the new HC HP will have a real narrow viewing cone.

Regarding the use of a grey substrate. I'm trying to get my head around it, but as I see it it can't increase contrast, only lower the black level together with the white level. If shooting with the same projector on the same type of screen (the same directionality) but one with a white substrate and one with a grey - to me they would produce exactly the same contrast but the white one would be brighter.

Since brightness is a big asset in todays projector market (just read the JVC threads! - you pay BIG money for a high performance projector that also is bright), I don't really see what the grey substrate brings to the table? Well, unless you have a small screen...

Or am I missing something?
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post #3558 of 3787 Old 05-13-2011, 05:24 AM
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I am seeking a review sample of the High Contrast High Power from Da-Lite. We will see how it stacks up against the Black Diamond, which I reviewed here.

I have been hoping for some time that Da-Lite would take the High Power and use a darker substrate. Sometimes dreams come true.

I am actually hoping that the stated gain of 2.4 is an exaggeration, meaning that WOULD be the gain if this was a white screen. I think that if the actual gain is closer to 1 or 1.5 that this screen may really be something special.

Let's see.

Affable Nitwit
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post #3559 of 3787 Old 05-13-2011, 06:21 AM
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Quote:
Originally Posted by Tryg View Post

I saw the post that they now have a gray screen. Lets see how the response goes then in the fall I'll probably contact da-lite to work something up. It's been five years...maybe it's time to whip something new up

I was kind of hoping for a review of the 2.4 HP.. since the original 2.8 is only somewhat applicable to the current 2.4.
My bet is the "NEW" HCHP screen is just a 2.4 with some gray colorant added to the emulsifier that is now used to hold the micro beads on. I plan to order 2.4 and the new HC 2.4 samples to compare under a a microscope.
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post #3560 of 3787 Old 05-13-2011, 08:38 AM
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Quote:
Originally Posted by Drexler View Post

Millerwill,

The HP doesn't hotspot due to its retroreflective nature. Though I imagine the new HC HP will have a real narrow viewing cone.

Regarding the use of a grey substrate. I'm trying to get my head around it, but as I see it it can't increase contrast, only lower the black level together with the white level. If shooting with the same projector on the same type of screen (the same directionality) but one with a white substrate and one with a grey - to me they would produce exactly the same contrast but the white one would be brighter.

Since brightness is a big asset in todays projector market (just read the JVC threads! - you pay BIG money for a high performance projector that also is bright), I don't really see what the grey substrate brings to the table? Well, unless you have a small screen...

Or am I missing something?

I know that the normal HP's don't hotspot (I have a 2.8HP), but was just wondering whether the higher reflective surface of the HCHP2.4 might. I hope you're right, that it doesn't.

But I still having trouble getting my mind around the brightness and CR of the HC HP vs. the white HP. If they both have 2.4 gain, then they MUST give the same brightness (ftL) with the same pj; i.e., ftL = gain*lumens/(screen area), there's nothing in the eqn about whether the screen is white or gray. So it seems that the two screens would perform EXACTLY THE SAME except for the higher rejection of reflected light by the HC version because of its narrower viewing cone.

All empty speculation, of course, so it will be good to hear from people that see these. (I've also ordered samples of the white and HC 2.4HP.)
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post #3561 of 3787 Old 05-13-2011, 09:08 AM
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Quote:
Originally Posted by millerwill View Post

But I still having trouble getting my mind around the brightness and CR of the HC HP vs. the white HP. If they both have 2.4 gain, then they MUST give the same brightness (ftL) with the same pj; i.e., ftL = gain*lumens/(screen area), there's nothing in the eqn about whether the screen is white or gray. So it seems that the two screens would perform EXACTLY THE SAME except for the higher rejection of reflected light by the HC version because of its narrower viewing cone.

Did my discussion a few posts back (#3555) about how a lower gain screen effectively improves the contrast performance of the room make any sense?
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post #3562 of 3787 Old 05-13-2011, 09:19 AM
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Quote:
Originally Posted by millerwill View Post


Another concern is that Dalite quotes the viewing angle as 20 deg for the HC HP and 30 deg for the white HP. I thought they quoted 30 deg for the old 2.8 HP, but am not sure. But is does seem that the new HC HP has an even narrower viewing cone.

Which is quite predictable. The way gain works is by focusing light toward the desired viewing position. The more gain you apply, the more focusing of the light, the narrower the viewing angle. So even if the gray and white screen ultimately have the same gain rating, the gray screen needed more focusing of the light to get it to the same rating. Hence, narrower viewing angle.

Quote:
Originally Posted by millerwill View Post

And finally if the gains of the HC and white HP screens are the same, isn't their white level and black level the same? and thus their CR the same? The only difference would thus be in wall reflections, less for the HC because of its narrower viewing cone.

Yes. But since wall reflections can have effects on contrast, in a room with brighter walls the HC should do a better job preserving contrast.
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post #3563 of 3787 Old 05-13-2011, 09:42 AM
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Quote:
Originally Posted by R Harkness View Post

Which is quite predictable. The way gain works is by focusing light toward the desired viewing position. The more gain you apply, the more focusing of the light, the narrower the viewing angle. So even if the gray and white screen ultimately have the same gain rating, the gray screen needed more focusing of the light to get it to the same rating. Hence, narrower viewing angle.

Yes. But since wall reflections can have effects on contrast, in a room with brighter walls the HC should do a better job preserving contrast.

Good point, Rich. So maybe the optical coating (or whatever) of the HCHP is actually not more 'reflective', and thus susceptible to hotspotting, but simply focuses the light more narrowly, to make up for the light lost by the gray substrate. Makes sense.

Since I have black fabric on my side walls and ceiling (out about 8 ft from the screen wall), I'm not very susceptible to reflections. So the white HP might still be my best choice if I do replace my present HP2.8 for a larger screen. But for white walls/ceiling the HCHP could be much better if the narrower cone is no problem.
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post #3564 of 3787 Old 05-13-2011, 09:47 AM
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Quote:
Originally Posted by erkq View Post

Did my discussion a few posts back (#3555) about how a lower gain screen effectively improves the contrast performance of the room make any sense?

The point is that the HCHP is NOT a lower gain screen than the white HP, at least according to Dalite's info (though we'll wait to hear from ones who see it); they are both listed as 2.4 gain. The only way I see that they could differ is how the HCHP reduces wall reflections because of its narrower viewing cone, as RichH pointed out.

But again, DarinP has noted that white walls do NOT effect o/f CR, because when the light is 'off' there are no reflections, and when it is 'on' (100% IRE) the reflections are swamped by the light from the screen. Refections thus effect only the effective ANSI CR.
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post #3565 of 3787 Old 05-13-2011, 09:54 AM
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Quote:
Originally Posted by millerwill View Post

The point is that the HCHP is NOT a lower gain screen than the white HP, at least according to Dalite's info (though we'll wait to hear from ones who see it); they are both listed as 2.4 gain. The only way I see that they could differ is how the HCHP reduces wall reflections because of its narrower viewing cone, as RichH pointed out.

Yes, sorry... I got lost in an epiphany Hughman, et. al. provided for me. Does not apply in this case.

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But again, DarinP has noted that white walls do NOT effect o/f CR, because when the light is 'off' there are no reflections, and when it is 'on' (100% IRE) the reflections are swamped by the light from the screen. Refections thus effect only the effective ANSI CR.

Yes, ANSI CR would be the issue.
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post #3566 of 3787 Old 05-13-2011, 10:54 AM
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Quote:
Originally Posted by millerwill View Post

The only way I see that they could differ is how the HCHP reduces wall reflections because of its narrower viewing cone, as RichH pointed out.

That how I see it as well for this screen. They've made this screen more directional which should reduce further the negative ansi contrast effects ambient light from the sides walls, ceiling, and floor. Back wall needs to be well treated though, as you know.

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But again, DarinP has noted that white walls do NOT effect o/f CR, because when the light is 'off' there are no reflections, and when it is 'on' (100% IRE) the reflections are swamped by the light from the screen. Refections thus effect only the effective ANSI CR.

It was ansi contrast erkq and I were discussing.
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post #3567 of 3787 Old 05-13-2011, 12:47 PM
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Quote:
Originally Posted by millerwill View Post

I know that the normal HP's don't hotspot (I have a 2.8HP), but was just wondering whether the higher reflective surface of the HCHP2.4 might. I hope you're right, that it doesn't.

The new HP won't hotspot. It's pure physics.

Angular reflective screens with gain have aluminum particles that works like tiny diffuse mirrors. They reflect incoming light at an angle that is equal but opposite the incoming light. I.e. light falling in at a 15 degree angle from above will be reflected downward with a 15 degree angle (see illustration). Light that is hitting the sides of the screen will have a higher angle of incidence and will be directed outwards towards the walls to a higher degree compared to light hitting the center of the screen which will mostly be reflected straight back to the viewer. Thus the center will be brighter and hotspotting happens. The further back you can put the projector the smaller the difference in angle of incidence between the center and sides of the screen and the less hotspotting you will see.


The HP however gets its gain from microscopic glass beads that collects incoming light and sends it back to the source. Light coming in at 15 degrees from above will be sent back 15 degrees upwards. And light hitting the far sides of the screen will be directed back towards the projector the same way that like light hitting the center of the screen - thus you get the same gain at the center and the sides and equal brightness all over the screen. No hotspotting.



So no matter how much beads they will add to the substrate to increase the gain and directionality it will not hotspot. Of this I'm sure.
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post #3568 of 3787 Old 05-13-2011, 02:42 PM
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Quote:
Originally Posted by Drexler View Post

The new HP won't hotspot. It's pure physics.

Angular reflective screens with gain have aluminum particles that works like tiny diffuse mirrors. They reflect incoming light at an angle that is equal but opposite the incoming light. I.e. light falling in at a 15 degree angle from above will be reflected downward with a 15 degree angle (see illustration). Light that is hitting the sides of the screen will have a higher angle of incidence and will be directed outwards towards the walls to a higher degree compared to light hitting the center of the screen which will mostly be reflected straight back to the viewer. Thus the center will be brighter and hotspotting happens. The further back you can put the projector the smaller the difference in angle of incidence between the center and sides of the screen and the less hotspotting you will see.


The HP however gets its gain from microscopic glass beads that collects incoming light and sends it back to the source. Light coming in at 15 degrees from above will be sent back 15 degrees upwards. And light hitting the far sides of the screen will be directed back towards the projector the same way that like light hitting the center of the screen - thus you get the same gain at the center and the sides and equal brightness all over the screen. No hotspotting.



So no matter how much beads they will add to the substrate to increase the gain and directionality it will not hotspot. Of this I'm sure.

Thanks--and great illustration!
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post #3569 of 3787 Old 06-10-2011, 09:47 AM
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Just set up my new 88'' HP 2.4 with my panasonic AE4000 to replace my white wall and the difference is big. Much better contrast and just seems sharper and bolder. The black borders really add to frame the picture. V happy so far
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post #3570 of 3787 Old 06-25-2011, 07:54 PM
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Quote:
Originally Posted by avswilier View Post

Just set up my new 88'' HP 2.4 with my panasonic AE4000 to replace my white wall and the difference is big. Much better contrast and just seems sharper and bolder. The black borders really add to frame the picture. V happy so far

Nice to hear. An HP screen vs a white wall should be quite the improvement.

Stephen.

Chances are very good that I was drinking when I posted the above.

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