Increasing Perception of Black Level - AVS Forum
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post #1 of 9 Old 02-12-2001, 12:45 PM - Thread Starter
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OK guys,

I'm thinking out loud here since I have not had the opportunity to test this, so I want to know if anyone has tried it or what you think of the idea.
I borrowed this link from another thread here.
http://homepage.mac.com/ccrim/home-theatre/screens.html

It shows some screen shots of one of our members tests of various screen material using a Sony 10HT projector (excellent page BTW). What I want you to take note of is the way the black edge of the screen makes the black of space look more gray. Now we all know that much of what we percieve visually is an optical illusion, in other words, we don't always see what is really there. The black of space looks gray BECAUSE the black boarder makes it obvious to the mind.

In my theater, I have a pull down screen (4/3) and one painted on the wall (235:1). The rest of the wall is painted flat black. This makes the blacks produced by my LCD projector to appear very gray, because of the very noticable change of shade.

My theory is, if I paint the wall surrounding my (painted) screen a very dark gray, instead of black, then the mind would be fooled into thinking the black of the picture is much blacker than it really is. A gray screen surrounded by a very dark gray wall (without the black edges around the screen) might produce a much more satisfying result.

Is this idea "washed out"? http://www.avsforum.com/ubb/smile.gif

Ken
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post #2 of 9 Old 02-12-2001, 04:22 PM
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Ken, common sense tells me this is an excellent idea of course there are others here with more experience with these matters than me that might be able to shed more light (pun intended) on the subject than I can. I wouldn't know why you couldn't do the whole room in a nice gray. I would think this would be perfect so the light wouldn't be reflected throughout. That link is a great source of information also. Looking at the different screen gains and seeing the result really makes me imagine just how good a gray screen can be. Of course another option is perhaps leaving the screen wall white and do the rest of the room darker to avoid reflections. Then your perception might be that screen black is even more black than what a screen wall of gray might give you. Just a thought anyways.
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post #3 of 9 Old 02-13-2001, 03:15 AM
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Theses tests let me feel Da-Lite made a mistake with its new grey Da-Mat HC fabric. Instead of spending time and money developping this new fabric, which BTW seems to be not a consensus contrary to the Stewart Grawhawk, they should promote and reconsider the "Super Wonder Lite" and make it available on bigger sizes: they're limited as 70" max wide only because the machine used to cut it is that width.
Really a shame...

I hope Da-Lite is hearing this.

Do someone share this same "feeling"?

Carlos

[This message has been edited by car_rod (edited 02-13-2001).]
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post #4 of 9 Old 02-13-2001, 06:30 AM
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Quote:
Originally posted by car_rod:
Theses tests let me feel Da-Lite made a mistake with its new grey Da-Mat HC fabric. Instead of spending time and money developing this new fabric, which BTW seems to be not a consensus contrary to the Stewart Grawhawk, they should promote and reconsider the "Super Wonder Lite" and make it available on bigger sizes: they're limited as 70" max wide only because the machine used to cut it is that width.
Really a shame...

I hope Da-Lite is hearing this.

Do someone share this same "feeling"?

Carlos

[This message has been edited by car_rod (edited 02-13-2001).]
Carlos,

Yes, I am listening and hearing what you are saying. However, what you need to know is that the tooling that is used to make the Super Wonderlite fabric only allows us to make the rolls of fabric in the 70" width. You see this material is made by special rollers that emboss the fabric (for the lenticular lines) and they can only be made in the 70" size at this time. Also, I should say the that Super Wonderlite fabric was great years ago when you did not have to worry about resolution issues (when all we used were 8mm and slide projectors). Nowadays we have to worry about that a great deal, I mean after all who of us if we were buying a new projector would not buy one with at least a 1024 x 768 panel in it? What I am saying is that we don't want the resolution of the projector to be affected by the lenticular lines on the screen. If it does, we can cause pattern issues such as Moire and other problems. You see if we end up not having at least 2 or 3 lines per pixel we can have problems. Therefore, in my opinion the Super Wonderlite is a "Blast from the past" and should not be used with the high resolution projectors that are on the market today. You might be saying, O.K. then just don't emboss the material. Well if we don't do that then all you have is a very high gain silver screen that has a greater tendency to HOTSPOT and we don't want that. I might also add that this material is very hard to work with and is limited to the number of screens that we can place it on.

Now, having said that. If it is the black level that you are trying to enhance by using this fabric you need to once again consider the HC Da-Mat fabric. I am not sure, Carlos, if you have gotten a recent sample of the material but if not please get one. The original samples that were sent were cut from the wrong roll and the gain was actually 0.6 and not 0.8. The correct fabric is quite a bit more white and until you look at it next to a regular Da-Mat screen you cannot tell it is grey.

Anyway, I just wanted to let you know that we do hear you but it just is not something we can do (make the Super Wonderlite bigger that is).

Thanks,



------------------
Blake

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post #5 of 9 Old 02-15-2001, 02:33 AM
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Quote:
Originally posted by Blake Brubaker - Da-Lite:
Carlos,

Yes, I am listening and hearing what you are saying. However, what you need to know is that the tooling that is used to make the Super Wonderlite fabric only allows us to make the rolls of fabric in the 70" width. You see this material is made by special rollers that emboss the fabric (for the lenticular lines) and they can only be made in the 70" size at this time. Also, I should say that the Super Wonderlite fabric was great years ago when you did not have to worry about resolution issues (when all we used were 8mm and slide projectors). Nowadays we have to worry about that a great deal, I mean after all who of us if we were buying a new projector would not buy one with at least a 1024x768 panel in it?
...
Blake,
First of all, thank you very much. It's amazing to see that manufacturers are participating in Forum with us, consumers or maybe just HT enthousiast people. We just need to thank them gladly.

Da-Lite tools for manufacturing the "old" Super WonderLite rolls are 70" wide maximum. I assume Da-Lite should invest to have wider tools with smaller embossed textures and this investment may not be worth the profit return. I understand that.

I own the well known projector Sony VPL-VW10HT which has 1366 pixels horizontal resolution. With a screen width of 80" this means a pixel width of about 1.5 mm (milimeters; 80" / 1366 = ~1.5 mm). I agree, in that condition the lenticular lines shouln't be more than 1 mm width; maybe, but not sure. Actually, how wide are the lenticular lines on the Super WonderLite?

I'm currently using an old screen that is only 50" wide. This is my father's 60's screen originally used for 8mm and positive photos. This screen is semi-gloss white and embossed with a honeycomb pattern like this:
\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/
Â*| | | | | | | | | | | |
Â*| | | | | | | | | | | |
/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\
| | | | | | | | | | | | |
| | | | | | | | | | | | |
\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/
Â*| | | | | | | | | | | |
Â*| | | | | | | | | | | |
/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\

At normal distance viewing, it looks like it was vertically embossed with very thin lines. The hexagones' width are about 0.7 mm or 0.8 mm and I never seen any moiré or undesirable texture effect (the pixels being about 0.9 mm in this 50" wide screen with my projector; 50" / 1366 = ~0.9 mm).

Quote:
Therefore, in my opinion the Super Wonderlite is a "Blast from the past" and should not be used with the high resolution projectors that are on the market today.
This definitively needs to be verified. But not by Da-Lite.
If I remember well, Da-Lite do not recommend his HighPower fabric with this particular Sony projector, but after reading users' satisfactory comments on the TheBigPictureDVD forum, the HighPower seems to be one of the best matching fabric for this projector and probably also for many other LCD and DLP projectors.

Quote:
You might be saying, O.K. then just don't emboss the material. Well if we don't do that then all you have is a very high gain silver screen that has a greater tendency to HOTSPOT and we don't want that.
No, I agree with you. From all test I did trying to make a screen myself, the best image I ever obtained was still with my old father's screen and with draft random embossed wall paper paint (uniformly white painted).
I borrowed a friend's screen which was silver and apparently with high gain but flat and not textured at all: the hotspot was horrible, you're right, but outside the hotspot the picture was amazingly deep and colored.

Quote:
I might also add that this material is very hard to work with and is limited to the number of screens that we can place it on.
Which are they? Can it be available with a fixed frame, say the Permwall or the Da-Snap? Or only on a tripod as we could see on Da-Lite website?

Quote:
Now, having said that. If it is the black level that you are trying to enhance by using this fabric you need to once again consider the HC Da-Mat fabric. I am not sure, Carlos, if you have gotten a recent sample of the material but if not please get one.
...
Anyway, I just wanted to let you know that we do hear you but it just is not something we can do (make the Super Wonderlite bigger that is).
Thanks again, I really appreciate your answer and your offer for samples. I didn't get any. But I have to be fair with you: I just ordered a Stewart Grawhawk screen from avscience, two days ago, before your post (you can ask Jason Turk from avscience).
Nevertheless, I'm still interested to get some samples (Super WonderLite, HighPower, Da-Mat and HC Da-Mat). I'm even interested to get a true Super WonderLite screen on a fixed frame and custom sized 70"x39" (16/9). This size should meet Da-Lite tool rollers. I just hope you can sell me at a dealer price as the purpose will essentially be for testing and comparing. Ask Jason for my actual name and address or contact me at car_rod@hotmail.com . Of course, I will report all my findings after testing.
I live in Belgium (Europe) and will take shipping fees at my charge.

Blake, thanks again. I really hope you will contact me and propose me something with the Super WonderLite. If it can't be custom sized at 70"x39" on a fixed frame then I will live with Da-Lite standard square 70"x70" tripod (shouldn't be a very attractive screen like this).

Carlos


[This message has been edited by car_rod (edited 02-15-2001).]
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post #6 of 9 Old 02-15-2001, 01:47 PM
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Greg,

As of right now we have not established a trade in/upgrade policy on the new HC Da-Mat fabric. The only thing I can suggest is going back through the dealer you purchased it from and discussing the option of returning yours for credit (less a restocking fee) and then purchasing the new screen.

Thanks for the question,

------------------
Blake

[This message has been edited by Blake Brubaker - Da-Lite (edited 02-15-2001).]

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post #7 of 9 Old 02-15-2001, 02:06 PM
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Carlos,

First, to answer your question regarding the width of the lenticulations the Super Wonderlite, they are 0.64mm wide.

In one of the paragraphs you mentioned that we did not recommend the High Power fabric with that particular Sony projector. I would like to clarify that and say that we discouraged people from using it when they were ceiling mounting their projectors. That is because of the nature of the fabric and it's retro-reflective characteristics. However, the thing to remember is that after the 30 degree half angle of the fabric, it performs like a matte white screen. That is why some of the forum posters have raved about the fabric's performance.

As for the screen models that are able to accept the Super Wonderlite, they are limited to just two models. Those models are the Deluxe Model B and the Picture King Tripod screen. Both are manual screens and since most people would not like to bring a tripod out for their Home Theater the closest solution is the Deluxe Model B. To that I might add my personal opinion and based on the money I would have to put into my projector, I would not want to project it onto a simple pull down screen.
However if you have your heart set on the Super Wonderlite that seems to be the only alternative.

As for your question about the Perm-Wall or Da-Snap, unfortunately no we cannot put the Super Wonderlite on those screens. In order to be put on those frames the fabric needs to be somewhat flexible and the Super Wonderlite is not. (Sorry to be the bearer of bad news)

Thanks for your candidness regarding your ordering a Stewart screen. Good luck and have fun with your Theater.

Best regards,


------------------
Blake

[This message has been edited by Blake Brubaker - Da-Lite (edited 02-15-2001).]

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post #8 of 9 Old 02-16-2001, 05:02 AM
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Quote:
Originally posted by Blake Brubaker - Da-Lite:
First, to answer your question regarding the width of the lenticulations the Super Wonderlite, they are 0.64mm wide.

...
However if you have your heart set on the Super Wonderlite that seems to be the only alternative.
Once again, thanks Blake.

You're right, I have my heart set on the Super WonderLite. And when you said the lenticulations' width is only 0.64mm, I've definitively fallen in love http://www.avsforum.com/ubb/wink.gif

So the screens available are "Deluxe Model B" or "Picture King Tripod". Isn't there a third option to get the fabric Super WonderLite alone, I mean just the fabric custom sized at 70"x40"?

Sorry for insisting, but you did a perfect job: you convinced me for this fabric (or maybe a bad job if your purpose is to promote the other Da-Lite fabrics http://www.avsforum.com/ubb/wink.gif).

Could you, please, tell me who I can contact for a quote in the US? Remember, I'm in Belgium (Europe): the Da-Lite catalog here is so big that it can fit on a mail stamp. 16/9 screens are available from 92"x52" minimum, and fixed screens are only available with the Cinema Vision fabric: a nightmare. I also saw an ad in France for the Super WonderLite on the Picture King tripod, only the size 50"x50" was available; did I already said a nightmare?

Thanks, Blake.
I hope you'll help me to put my hands on this fabric.

Carlos

PS: here is a page from Da-Lite's website http://www.dalite.com/products/catal...product_id=230
It seems Super WonderLite is available on much wider sizes than 70", BTW, a model C screen. Is this a mistake?
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post #9 of 9 Old 02-18-2001, 09:57 PM - Thread Starter
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This thread went off in a strange direction. http://www.avsforum.com/ubb/smile.gif

Back to the point, I've done some testing and discovered this is a bad idea. Most digital projectors do not use their full panels, a small band of pixels are unused around the edge (LCD projectors anyway). This band becomes very obvious and distracting when the area around the screen is dark gray instead of black. It makes the gray shading of the blacks even more obvious. The black edges of the screen and surrounding wall hide this light spill very well.

I will stick with my flat black wall around the screen.

A gray screen is another matter.......

http://www.avsforum.com/ubb/smile.gif

Ken
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