Breakthrough in ambient light rejecting screen - Page 4 - AVS Forum
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post #91 of 112 Old 11-02-2006, 07:49 PM
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I never come to the Screen forums, but I'm getting ready to move and when I go I'm getting a new setup with a 720p PJ and a new screen (the current one is a modified pull-down; very lame). Anyhoo- I thought this was a great thread. I have always actually wondered exactly "how dark is too dark?" in a screen; I've always assumed that grey screens must skew the white levels of an image and have stuck to a matte white screen in a VERY dark room. So this was a total eye-opener for me. Extremely fascinating stuff.

Don't taze me, bro!!
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post #92 of 112 Old 11-03-2006, 03:44 AM - Thread Starter
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Quote:
Originally Posted by FredProgGH View Post

I never come to the Screen forums, but I'm getting ready to move and when I go I'm getting a new setup with a 720p PJ and a new screen (the current one is a modified pull-down; very lame). Anyhoo- I thought this was a great thread. I have always actually wondered exactly "how dark is too dark?" in a screen; I've always assumed that grey screens must skew the white levels of an image and have stuck to a matte white screen in a VERY dark room. So this was a total eye-opener for me. Extremely fascinating stuff.


Fred
Glad you enjoyed it, and also glad you saw the connection.
I actually saw the effect of this long before the light came on for me. It was kind of like going on trust from what others said. The more I got into this idea of a neutral shading of white it became clearer to me. Then when I realized that in most paint mixes the pigments really don't combine but just sit there side by side as tiny particles in varied proportions. It's the fact the pigment particles are so small our vision can't resolve on just a single bit of pigment we then see them as a combined reflectance. On the other hand light striking the surface reflects or is absorbed particle by particle.
Like a mixture of salt and pepper the salt sending back most of the color correctly because it's white and the pepper absorbing most. That's in paint.
In the case of my paper screen even though the paper looked pretty black it wasn't a pure black body. It had some surface sheen and was a very dark shade of gray I'm sure. I didn't think to measure the surface temperature of the screen before and after projecting but that extra energy was going someplace and my guess is heat.

Fred with the new projector if you have a few lumens left over don't be afraid to try some of the mixes here now. And don't be afraid of gray messing the whites up to much. As long as you have enough light you will be ok. And much better IMO than a ND filter for those with extra lumens.


Bud

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post #93 of 112 Old 11-03-2006, 05:28 AM
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oh Bud, you should know by now that nothing suprises me around here.

"The only reason you're still conscious is because I don't want to carry you" - Jack Bauer
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post #94 of 112 Old 11-03-2006, 05:34 AM - Thread Starter
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Quote:
Originally Posted by biglyle View Post

oh Bud, you should know by now that nothing suprises me around here.

Not much surprises me here ether anymore, but I'm pleasantly surprised you are still reading the thread.


Bud

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post #95 of 112 Old 11-03-2006, 06:04 PM
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I think I may go with either the Optoma H70 if I decide to pinch pennies or the Mits HC3100 if I decide to spend more (and can find one). I'm still trying to weigh options. AFAIK the Mits has lumens to spare but I don't know about the Optoma. I really haven't decided if I feel froggy enough to DIY a screen yet...

And I think you are right about black paper not really being all THAT black, it's just colored black. It would be interesting to project on a slab of onyx or something. Still, the paper is pretty dark and you clearly had great white levels and color saturation. Makes one think- anything could be around the corner with technology. One day black screens and giga-lumen projectors might be commonplace *lol*

Don't taze me, bro!!
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post #96 of 112 Old 11-09-2006, 11:19 PM
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Bud...

Based on your experiment, have you considered trying a few more sample screens with increasing amounts of black pigment in your "Simple Screen Paint Solution" and a 1:1 poly to water topcoat?

This may become very practical since a lot of people seem to be buying the AX100. It could use the increased black level and has the ability to produce a significant number of lumens.

Krister
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post #97 of 112 Old 11-10-2006, 05:18 AM - Thread Starter
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Quote:
Originally Posted by krholmberg View Post

Bud...

Based on your experiment, have you considered trying a few more sample screens with increasing amounts of black pigment in your "Simple Screen Paint Solution" and a 1:1 poly to water topcoat?

This may become very practical since a lot of people seem to be buying the AX100. It could use the increased black level and has the ability to produce a significant number of lumens.


Krholmberg

That was pretty much what I wanted people to try with that thread and report back what worked and why.

One of the problems I have or most DIYers have is I just have one projector. Its my belief that suiting the projector to the screen is a big deal. And not just the projector / screen but also screen size and ambient room lighting levels.

That's partly why I tried the black screen experiment. I thought what can I do at home in my basement testing lab / home theater that could simulate different peoples projectors and conditions. And knowing my projector is of fairly high lumens I thought I could get an assortment of ND filters and by using them I could mock up lower lumen projectors kind of I also saw I could move my test screens in and out to get different FL readings under these different light levels. That's when I thought ok I can get to any FL I need by moving the screen and if I relate them to neutral gray scales and see ambient performance improvement as FL go up how far can I go. Thus the black experiment. Sure that was an extreme example.
But I read a lot of posts where people are using projectors like the AX100 you mentioned shooting to some pretty small screens. Keep in mind each time you half the throw distance the FL go up by 4. so a 60 inch screen is 4 times as bright as a 120 inch screen.

Last week member movielvr2006 commented on how dark a neutral gray he went to with a smaller screen size and a fairly bright projector. And the great black levels he was seeing with some ambient.

So yes its out there if anyone wants to experiment with the idea.


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post #98 of 112 Old 11-10-2006, 06:33 AM
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Tiddler's last entry pretty much sums up the most pratical way to get to a point where you have gains without losses.

I'm going to be seeing how a 68" x 38" 16:9 BFLF screen performs with a AX100U today. PJ is at 13' back. Screen is mounted over a Fireplace.

The "hue' will be identical to the screen seen in the "A Friend in need" thread. Same paint actually.

As Bud stated, his experiment was "extreme" and the results wholly dependent on blasting excessive lumens from arm's length onto the black surface. Nothing completely "Black" currently out there can duplicate the same results in 80"+ sizes with nornal levels of PJ illumination coming from over 11" back.

No matter what, other factors and components MUST come into play to be able to begin to reach such levels of pure ambient light watchability. At some point, the use of a "Grey" in darker hues will reach a point of diminshing returns because the darkness of the hue exceeds the PJ's ability to compensate. Even such an application as a dark hued BF is totally dependent on the correct match up of a correspondingly bright PJ. The adjustability of such a mix makes it more readily usable in most any application, but there is still the need to do such adjustment in order to acheive the maximum benefit.

The Panny's 2000 lumens makes the accomplishing of such endeavors more realistic and acheivable, but even so, common sense and practicality must rule.

To quote James T. Kirk;
"I'm laughing at the superior intellect"


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post #99 of 112 Old 11-10-2006, 06:40 AM - Thread Starter
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Tiddler

Finally lol

I have been trying to get across for some time just how slight a shade of neutral gray I have been advocating. And how big the results can be. I would put my projector in maybe the top 10% when it comes to brightness and the shade of neutral gray I selected is way down the sliding scale of grays that are talked about here.

Do the comparison as Tiddler mentioned I prefer comparing samples one at a time against a white screen. I used BOC as a base and advocated that in my thread because its something cheep and also something everyone can get their hands on a yard of. That way when we talk or view screen shots we are all on close to the same page.

I actually did my comparison at first with just the small paint cards you get for free at the paint store. I wasn't looking for overall PQ just areas on a frozen image where white and black came together. The slightest of gray deepened the blacks just as Tiddler said and whites seemed to change very little. There was a point when I could see a slight diminishment in white and that's where I stopped.

The resulting image was LOTS better than white alone and then the addition of the poly paint blend gave a slight improvement in brightness but gave an overall PQ increase in appearance. The word I want to use is not right there and it's something you have to see to know if its what you like. Glow, Shimmer, Transparent, Pop. Pick one

I ended up tailoring my screen to my new projector set on eco mode and brightness at zero with no boosts color 7500k all other settings at zero. I did this knowing throughout the life of the bulb I would need to bump it up from time to time by some means. That's how I would suggest others approach this also.

Side note: conventional wisdom tells us that lampblack mixes are known to result in a blue push. When calibration showed and I concurred by my own taste that 7500k was right for me based off of skin tones etc. I was once again a little surprised. I would have thought I would have had to go to a warmer 6500k at least.
Still haven't figured that one out.


Bud

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post #100 of 112 Old 11-10-2006, 01:29 PM
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Very interesting stuff. I'm interested in making a 112" diag 235:1 screen with Bud's painting technique, but am a bit concerned about the size. If smaller, I probably would get some Do-Able board and see if I like the results. I'd also cut off a bit to the side, paint it with the chosen mix, and then hold it up and see if I like it more. If so, then I'd paint the rest of the board. If not, I'd leave the Do-Able board as is. But, the size I'm looking for is bigger than what is handy to get. 10' x ?' MDF would be workable, but hard to get. I like Bud's canvas a lot, too, but that seems kind of hard to manufacture.

Krister
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post #101 of 112 Old 11-10-2006, 01:55 PM
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So with a higher lume projector you can have a darker grey screen, right? And therefore have better ambiemt light veiwing while being able to maintain black and white levels , right? I'm more than likely going with a Sharp XR-10x which should be plenty bright.

later
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post #102 of 112 Old 11-18-2006, 01:12 AM
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How does this compare to a DNP Supernova / Screen Innovations Mirage?
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post #103 of 112 Old 11-18-2006, 06:59 AM
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Lol, there is just so much info to read, I cant keep up. Wasnt gonna wade through the whole thread.
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post #104 of 112 Old 11-19-2006, 06:53 AM - Thread Starter
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Quote:
Originally Posted by tiddler View Post

This thread was a joke to prove a point. It is NOT a practical application for a projection screen.

Bud, I really think you should get the administrators to change the thread title to something that is not so misleading.

Tiddler

First off I did change the title on November 1, and also added a lengthy disclaimer not to the end of post 1 but to the beginning of it. I can't help it if someone only reads the end of a thread and makes some assumptions as to what is going on in the thread. I often read the last entries of posts I haven't been following but I always take the time to go back to post 1 and try and find out where it all started. And I do at times skip the bulk of the center of a thread if it's something I'm only slightly interested in.

I did not though start the thread as a joke and I didn't infer that in the amendment to post one. In fact I was trying to demonstrate a real world, true, aspect of projecting to a neutral gray screen, and the fact that the darkness of the gray doesn't inhibit the reflection of the color white.

I did craft the thread in a method most are unaccustomed to me doing and in doing so I think I drew attention to the thread and also made something a bit boring more fun. That was my goal but many didn't get it. The fact that some didn't get it and became emotional within a hour of the first post did illustrate the knee jerk reactions that seem to run rampant only in this forum.

(People keep in mind this is FUN!!!)

The nice part of it was some people did get the point and at least a dozen have written and said that the thread and the illustrative photos caused a light to come on in their way of contemplating a gray screen, and at the same time enjoyed trying to solve the puzzle.

The ironic thing is this thread raced to 3 pages and surpassed the thread I started laying out the exact same information in my original (simple screen paint) thread.

I do believe from PM's I have received the thread brought several new minds into the forum that might stick around and contribute.


Bud

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post #105 of 112 Old 11-19-2006, 07:08 AM - Thread Starter
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Quote:
Originally Posted by krholmberg View Post

Very interesting stuff. I'm interested in making a 112" diag 235:1 screen with Bud's painting technique, but am a bit concerned about the size. If smaller, I probably would get some Do-Able board and see if I like the results. I'd also cut off a bit to the side, paint it with the chosen mix, and then hold it up and see if I like it more. If so, then I'd paint the rest of the board. If not, I'd leave the Do-Able board as is. But, the size I'm looking for is bigger than what is handy to get. 10' x ?' MDF would be workable, but hard to get. I like Bud's canvas a lot, too, but that seems kind of hard to manufacture.

Krholmberg

I'm glad you read thru my other thread and I'm assuming that's the approach you were talking about following.

Don't make a 112 pure black screen. ok unless you have a very bright room and a huge light canon.

I do understand the problems associated with trying to make a screen in sizes larger than normal materials come in. that's what I was faced with and why I started the canvas screen thread. Pretty much finishing a smooth wall and painting it is the other approach and also the large plastic sheets like MM often shows.

The screen I built looks a little harder than it is but I wouldn't call it simple. My friend just built a variation on it and he didn't have too much trouble.

I also hope you review all the screen types and screen surface options throughout this forum and make an informed pick based on your room, projector, budget and abilities. Good luck


Bud

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post #106 of 112 Old 06-23-2007, 07:15 PM
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Hey Bud, are you going to bump this thread?
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post #107 of 112 Old 06-24-2007, 10:08 AM - Thread Starter
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Quote:
Originally Posted by prof55 View Post

Hey Bud, are you going to bump this thread?


Oct 30 2006 was a fun day watching the replies to this OP come in and the subsequent banter.

Prof55
I was going to give it a bump but I read some place today that doing that is self-serving or something. So thanks for doing it for me.

Actually I was hoping the thread would pass into the archives and I could wait a little while for enough new comers to move in that I could start it over again and have all that fun again.

Oh I'm sure I can figure out something new now.


Bud

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post #108 of 112 Old 03-05-2008, 12:45 PM
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I enjoyed the read...wouldn't consider it "clutter" at all. Thanks, Bud.
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post #109 of 112 Old 03-12-2009, 04:09 PM
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Thanks. Informative.
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post #110 of 112 Old 03-12-2009, 04:10 PM
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Hey whoever owns this forum....make this a sticky!!!!
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post #111 of 112 Old 03-13-2009, 09:27 AM - Thread Starter
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Quote:
Originally Posted by heislord5 View Post

Hey whoever owns this forum....make this a sticky!!!!

This thread was kind of sticky the day I posted it. It's not quite as much fun to read with the disclaimer in the OP before you read it but it's still fun and somewhat informative.

I'm still waiting for a 50,000 lumen projector so I can go black on my 120 screen. for now best I can do is gray.

Thanks for reading guys.


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post #112 of 112 Old 05-04-2010, 01:58 PM
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I read at least half of these posts, starting from the first. Thanks bud for showing that gray is the same color as white, just darker. I'll have to do some more thinking on this to see if a gray screen is good for me.
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