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Discussion Starter · #1 ·
I began this post under an RLEV thread but have decided to repost here and complete it here.


There have been posts during the 39 pages before this post that question the "luminosity" and or "opaqueness" of this product.


RLEV introduced me to this product and also to the idea of its possible light transfer properties. Regretably he did not do any before and after screenshots or tests, only an after test.


My first basic test of this product is listed below with photos in additional posts. This is in no way a scientific study, since I am in ahurry and I am also trying to finish my theatre. I have NO CLUE how a 500 watt halogen compares to a 3 gun 1100 lumen CRT or a DLP/LCD - maybe someone can give me some idea of a comparison.


Parkland Matte white 4 x 8 from Menards...total cost under $12.


Here is the initial test with a 500 watt halogen workshop light sitting inside a roll of the material approx 12" from the rear surface.


Room was very dark - slight bit of light.


Obviously the material transfers light thru one layer- so we can disregard any previous post that says light will not penetrate it. FACT: bright light will penetrate the product.


More Screenshots to follow in more threads.
 

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Discussion Starter · #2 ·
PARKLAND is set across door opening with bulb 4 feet away from rear surface.

Light is in a small bathroom with bathlights off.


Still transferring light.
 

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Discussion Starter · #3 ·
SAME DOORWAY 6 FEET from rear surface


Same bathroom with bathroom light off .


Still showing a lot of light transfer.
 

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Discussion Starter · #4 ·
Bulb now in dark hallway with bulb 8 feet from the rear of the surface.


Still the same amount of light transfer.



What do you guys think of the results? It seems a regular projector would push less bright white light thru with a movie on it.


I also see the material turns a warm yellow color...not sure how this effects color balance.


I plan to do a test while projecting an image onto the front surface and taking a photo of the rear.


This will take some time.


If anyone else would like to jump in and try it that would be great.


Again - totally non scientific test. Just curious and wanting to prove this one way or the other.
 

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I don't read many of the threads in this forum, but do drop in on some of the Parkland topics. If anyone has ever stated that Parkland does not transfer light through it, they are simply wrong. If you shoot a movie onto a sheet of Parkland and look at the back of the sheet, you can see the movie. It is substantially dimmer than the front and not as clear, but it is there.


Where some of the debate has been is about if one coats the back of Parkland with either a reflective or light-absorbing material, will it make a visible difference to the projected image as perceived by the viewer. I've conducted numerous experiments, such as coating the backside with silver metallic, taping a mirror to the back, painting the back black, red, and gray, and taping various colors of construction paper to the back. Also I've played around with shooting images against a two-layer thick sheet of Parkland to see how much light from a typical movie would get through at typical screen projection distances (the answer was that essentially no light got through).


What I've observed to date is that I have yet to find anything done to the back side of a sheet of Parkland that makes even the slightest difference to projected image. Furthermore, as you point out, the image/light that is transmitted through is degraded in both color purity and focus. Thus if one could come up with some way of reflecting that light back through the Parkland again (and thus degrading it again) to the point of it being bright enough to make a difference, then the difference would certainly have a negative impact.


So yes it does transfer light and that is something that you should be aware of if you have a light source located behind your screen. Let's say you have a hanging sheet of Parkland and there is a window behind it and you watch movies on it during daylight. If so, it would be best to cover the backside with wood or cardboard or you could try painting it black to reduce the light transfer.


One might be worried that by having their Parkland mounted on an open-back wood frame over a white wall and thus reflected light coming off the white wall would act as a light source behind the screen. I've tested this and the amount of light being reflected is very low, not nearly enough to make a difference. But if one wants peace of mind, they could use a backcovering or dark paint to make sure.
 

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Discussion Starter · #6 ·
Yes, there was a test done by a member with a 1/2 painted sheet and he claimed he could see no difference and no light came thru.



I had intended to do a 50/50 test with stock Parkland and silverbacked Parkland - but Mswauger already did the test. His photos show a clear winner. The silver backing improves NOT DEGRADES the picture.


Simply look at the following screenshots by Mswauger to end the debate.


The reflected light from the back is CLEARLY evident and does NOT degrade the picture, it makes it brighter, increases the color a bit and makes for deeper blacks.


End of story.

http://www.avsforum.com/avs-vb/showt...0&pagenumber=2


If someone decided it degraded the picture they could always paint the back black etc. Parkland is still a good surface vs, drywall and $$$ screens.
 

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A digital camera picture posted to a web page is certainly not going to outweigh my having directly viewed, on numerous occasions and being able to continue to do it whenever I wish because I still have it, a sheet of Parkland that was partially painted with silver metallic.


On my sheet of Parkland, the silver backing made absolutely no difference. That portion of the Parkland was not brighter and did not have increased colors or deeper blacks. I've even posted images of it to this forum, showing no difference. And I've had more than half a dozen people look at it and none of them saw a difference.


I would have liked it to make a difference, as my main screen is made of Parkland and I would be quite willing to paint the whole back if there was an improvement. But as you stated, facts are facts, and the fact of my screen was that there was (and is) no difference.


I do agree that Parkland is a good screen surface.
 

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Discussion Starter · #8 ·
1. The fact is RLEV noticed a difference while viewing but did not do a side by side and screenshot test - but he could see a difference and if I am not mistaken has to turn down his brightness and adjust other settings after the silver was applied.


2. Mswauger's pics show a clear difference - one of the photos it looks like someone drew a line right down the screen for crying out loud! I would say if he did more pics looking for scenes that were friendly to being split down the middle we would see even more examples.


I know it works - I wont be wondering or posting screenshots comparing - the Parkland arrives Tuesday, The silver paint is already here - the Parkland gets painted silver on the back Tuesday. Bammo... I have a better than average DIY screen. End of story.


If you want to split hairs about why you are not seeing anything maybe its because he had already applied different products to the front?


I am leaving mine bare white on the frontside.


Facts is facts - were you on the O.J. jury?
 

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I don't know why you are getting all bent out of shape about this. I've reported my findings here in a couple of threads and posted screen shots. In a nutshell, here is what I did:


I took a 12"x12" scape sheet of plain, unpainted Parkland and painted half of the back with two coats of Behr Silver Metallic paint.


I placed this square up against my large unpainted Parkland screen, that is mounted against a sheet of insulation foam that has a black surface. This made a total of three different test subjects with all of the fronts being unpainted Parkland. The backs were plain, silver metallic, and black.


I then shot a variety of test patterns and movie scenes against the screens. Actually did it three separate times, testing different things. Audience was myself, my wife, and two of my teenage daughters.


I then took the sample sheet of Parkland to work and put it up against a white matte pull-down screen (I believe it was Da-Lite, but would have to check my notes). I asked three co-workers to look at it to see if they could see any differences across the front image ... they did not know half of the back was painted and obviously did not know which half.


In the end, none of us could see any differences between the two halves of the Parkland sample. And of the four people who compared the sample vs the Parkland screen with a black backing, none could see a difference between the sample and the screen.


Now if I said that I had seen a difference, then the comparison to O.J. would be valid, as I would be lying.
 

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Discussion Starter · #10 ·
You should have showed it 12 - I think 12 are on a jury. I was making a joke because 4/5 of his pics are so obviously improved.


Anyway, have you looked at Mswaugers screenshots?


When you do...are you saying you dont see the difference?


Thats all I need to know, because if you cannot see the difference the discussion is pointless.



Are you telling me you used a 12" x 12" piece???? Thats in no way a comparison.


12" x 12" is not going to be the same as 1/2 sheet of 4 x 8 in my opinion


Thats what wrong - your talkin about a LOT LESS LIGHT overall hitting a surface of 12" x 12" vs 4' x 8'.


I have a 35 mph wind - you put a 12" x 12" sail up I put up a 4' x 8' sail - guess who gets there first?


I would think the same principle applies. If anyone here wants to do some mathematical calculations of reflectivity on 1 sq foot vs. 32 sq ft please do....but I am guessing it will be exponentially higher


Also - we are into video and quality and light and sharpness. We as home theatre guys see 1000 things others wont ever see! You cant use untrained eyes to test something that may be subtle to begin with.


Do you think any of your test subjects would complain about screen door at 12' or digitization on edges or other digital artifacts upon first viewing? Its just not the same thing as showing it to people who know what to look for.


I will be adding one extra coat to the backside of the parkland just for you :)
 

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If there was a visible difference, it should be evident on a 12"x12" sample when that sample is up against the full screen. I can see differences on the screen with 0.5"x0.5" areas when using very slightly different tints of gray paint.


I didn't just project solely onto the 12"x12" sample, although I did try that in my various attempts to see a difference. Nearly all of the tests were run against 80" diagonal images, with the 12"x12" being moved around into key areas of the test shots in order to try to find differences in fleshtones, bright colors, grays, and multi-color images.


I should note that those other "untrained" eyes did spot small differences on other sample screens, where I also saw differences. The co-workers I used were the staff who evaluate, repair, and calibrate computer monitors for a living.
 

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Discussion Starter · #12 ·
Quote:
Originally posted by Tom_Bombadil
If there was a visible difference, it should be evident on a 12"x12" also saw differences. The co-workers I used were the staff who evaluate, repair, and calibrate computer monitors for a living.


You are still ignoring the obvious evidence on this board.


Please go look at RLEV's post where he taped a piece of normal Parkland onto his improved Parkland. It was a color bar test pattern...even in that example you can see subtle difference in which his screen looks a bit brighter than the stock Parkland.


Once you have done that, please answer this question.

Do you see a difference?


Then please go look at the 6 examples Mswauger has in the same thread group and answer this question...

Do you see the difference?


Because if you cannot 100% agree there is a POSITIVE difference - there is no sense in going futher.


If we asked 100 people to look at those two posts I would venture to say that 75 would see the difference. No one would have bothered to post photos if there was not a clearly visible difference.


I have a 4x8 sheet of Parkland downstairs - if I was not so busy building my theatre I would show you once and for all...but you would still argue it cant be so because your 12" x 12" test proved nothing.

There is no reason - the shots are on the board and you wont admit they are proof.


HOW ABOUT A DIMLY LIT NORMAL 3" WIDE FLASHLIGHT - GUESS WHAT - AT 4' AWAY IT CLEARLY PROJECTS THRU THE PARKLAND.

Add silver paint on a 9' wide x 5' high surface and about 1000 times more light than that...its OBVIOUS whats going to happen. A ton of light is going to be coming back at the viewer improving the image.


Is it pure 100% halogen clarity filtered fusion activated ion light - hell no - but the screenshots show better black, contrast and better colors so who cares whats coming back if it makes the picture look better?




I will agree a 12" x 12" sample wont show anything.


Carada sent me 12" samples - they are useless in trying to imagine or judge what a surface would look like in a real situation at 32 sq ft or 50 sq ft.


There are countless other posts where everyone has expressed frustration at trying to tell anything from 12" x 12" samples.
 

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Discussion Starter · #13 ·
Quote:
Originally posted by Tom_Bombadil
I don't know why you are getting all bent out of shape about this. I've difference between the sample and the screen.


Now if I said that I had seen a difference, then the comparison to O.J. would be valid, as I would be lying.
Hmm... the screenshots must have finally spoken for themselves.


Ill add another coat of that silver metallic just to be safe.
 

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Sure, looking at the screen shots completely convinces me that it has an effect, even though the screen I have right in front of me shows no effect! Not!!!


I cannot duplicate the results of the originator of that thread. I've tried two projectors, each at two different light output settings, and cannot see any difference between the plain Parkland and Parkland backed with silver metallic. Although I can understand that if there is some light coming in from behind the screen, that blocking it with SM, black, cardboard, whatever, could possible make a difference under the right conditions.
 

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Discussion Starter · #15 ·
 http://www.avsforum.com/avs-vb/showt...0&pagenumber=2


I guess you could post your screenshots showing no difference on a 50/50 board to even this post out.


http://www.avsforum.com/avs-vb/showt...0&pagenumber=2


Both RLEV and Msawuager used some topcoats of different formulations - blame it on that.


I am painting mine because I see the difference clearly in the majority of his photos.


Now - a post showing where it began

http://www.avsforum.com/avs-vb/showt...0&pagenumber=2


Heres a quote

"As a matter of fact, I did precisley that this past weekend. I already had a ME painted screen and I un-mounted the Parkland from my wooden frame and coated the back with Behr Silver Metallic. I am extremely pleased with the results.


I did some 1/2 and 1/2 testing and will post some screen shots soon."



Here is the AVIA test where YET AGAIN you can see a difference !

http://www.avsforum.com/avs-vb/showt...hreadid=347790
 

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Discussion Starter · #16 ·
Quote:
Originally posted by Tom_Bombadil
some light coming in from behind the screen, that blocking it with SM, black, cardboard, whatever, could possible make a difference under the right conditions.
Thats all I am trying to say in all my posts - hey everyone the Parkland lets a ton of light thru - so block it somehow and why not block it with something that may just brighten the image in the end for pennies on the dollar.


Would a mirror behind the Parkland reflect light back? Yes.

So silver paint will not? It has to be true?
 

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So how does reflecting more light back into the screen from behind it, result in blacker blacks?


As to posting a screen shot, I already did that a few weeks ago in a different thread on this same topic. Pretty boring shot though as there is no change across it.


A reflective surface would reflect light, naturally. The question is that could it reflect enough light so that at normal projector & viewing distances, with the typical amount of light that would be cast upon a screen, to make a visible difference on the front surface.


Think about this - Compare the brightness level of the front of your Parkland to the back with the projection at its normal position. Then consider that the reflected light will drop by the same ratio as it passes back through the Parkland. That is, if the back is 1/10th as bright as the front, then the amount of reflected light that would come back through the front would end up being 1/10th of 1/10th, or 1/100th, of the brightness of the front surface. Then consider that your own experiments have shown that this reflected light is color-shifted and you can see off of the back image that it is not as sharp as the front. So you would have a color-shifted, out of focus, 1/100th as bright image coming through.


In the case of the original poster, his screen also had 4 coats of paint on it. So it would be only that light that could get through 4 coats of paint, a sheet of Parkland, hit a less than 100% reflective surface, go back through a sheet of Parkland, and then through the 4 coats of paint again. Sounds pretty difficult doesn't it?
 

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Discussion Starter · #18 ·
"Sounds difficult" has no bearing on the fact his pictures CLEARLY show a dividing line in which one side is brighter.


RLEV had to turn DOWN his brightness settings - this is NOT imaginary.


WOW ! In an effort to debunk the whole theory you pointed out something I was not even thinking about !


Mswauger is getting visible results through up to 4 extra layers of paint on the front side!


This makes the potential of my 9' x 5' Parkland with NO surface paint that much GREATER!


I am laying on the Silver Metallic heavy !


Thanks!
 

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Quote:
Originally posted by Tom_Bombadil
So how does reflecting more light back into the screen from behind it, result in blacker blacks?
Ok, I have theory on this one. The white or colored light coming from your projector has enough intensity to penetrate the Parkland and afterward still has enough luminosity to hit the backing material and be reflected back to some degree. The blacks do not have enough intensity to both penetrate and reflect.


The effect is that in areas where the projected light is more intense a brighter image is produced while blacks are truly left alone. This would change the perceived contrast of the image (ie. make the blacks look darker). Which, at least in my case with a LCD projector, is a good thing since I have only a 300:1 contrast ratio.
 

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Mike,

If I recall corectly, Mswager's screen is hanging out in the room, not against a wall or anything. I clearly see a difference in his shots, but the question I have is would this look the same if black paint had been used, or if the parkland was placed against a wall? My thoughts are that the unpainted side is being "bleached out" slightly from ambient light behind the screen. This ambient light could come from room sources, or from light passing through the screen itself illuminating the wall behind it, as you have proven in your shots above. I think painting the parkland is a good idea, just dont belive the silver is worth the extra cost over any other dark, light blocking pigment. (The fact is that blacks would actually be made lighter in color with added reflections from behind.)
 
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