Testing ALR Projector Screen paint - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 1 Old 06-09-19, 10:05 AM Thread Starter
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Join Date: Jun 2019
Location: Barcelona, Spain
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Testing ALR Projector Screen paint

Hi all

Thank you for contributing to the forum. I've found very useful information here!

After some time reading the threads and learning, I decided to share my experiences. Any comments are very appreciated.

I use a projector for watching the TV and movies at home, in a non-dedicate room with ambient light. Two months ago, I was going to watch the TV at midday, and I realized that was very tedious to close all the windows of the room each time I wanted to use the projector. So, I decided to start looking how can I improve that. After considering several options, I decided to buy a new brightness projector, the Epson EB-2042 with 4400 lumens. The difference with the previous one was impressive, mainly by the fact that the new projector uses the 3LCD technology and provides more brightness. So I was very happy with the change.

I have the projector at 4.7m from the projection wall with a 120" diagonal size. The estimated image brightness computed at projectorcentral website is 75 fL for a projector screen with gain 1.0. In ECO Mode, the image brightness is reduced by 50%.

However, after some days I started wondering if that could be improved. I started thinking on having a non-expensive ALR projector screen, so I started looking at the different options: buy a cheap one, buy the material or paint the wall. After looking at the different manufacturers, I realized these are too expensive, so I started trying the other two options.

Test protocol
To compare the different screens, I made the following rudimentary tests:
1. Dark Room test: Test white and black colors at the center of the screen in a dark room (windows closed)
2. Ambient Light Room test: Test white and black colors at the center of the screen in an ambient light room
3. Spotlight Dark Room test: Test white color in a dark room (windows closed) at the four corners of the projector screen: bottom left, top left, top right and bottom right.

The test consists of projecting an image with black or white colors, capture an image with my mobile using manual fixed settings and measure the luminance of the white and black colors in the image using the Windows Paint.

Testing screen materials samples
I ordered the following projector screen materials samples: MaxWhite, ProWhite and ProGray from PSM and CineGrey3D and CineGrey 5D from Elite Screens.

After testing the materials, the results were very interesting. The PSM materials does not have angular reflective properties, while the Elite Screens materials do. The Elite Screens materials have better blacks and better ALR. However, the hotspot effect is very high, specially for the CineGrey 3D at the top left corner. So I decided to start testing the screen paints.

Testing screen paints
I bought some of the recommended paints that I found in this forum and AVS forum and started testing. I live in Spain, so I can only test the paints that are available here. These are the mixes I tried:
1. FolkArt 1:1: 50% FolkArt Gunmetal Gray + 50% FolkArt Medium Gray
2. FolkArt 1:2: 75% FolkArt Gunmetal Gray + 25% FolkArt Medium Gray + a bit of water + a bit of white plastic paint
3. AAA + Plastic Paint: 20% AutoAir Metallic Fine + 80% White Plastic Mate Paint + some drops of black tint
4. AAA + FolkArt Grey: 50% AutoAir Metallic Fine + 50% FolkArt Medium Gray

As you can see, I could not find the Dulux paint locally. So I made the mixes using FolkArt Medium Gray or a standard White Plastic Mate paint.

After testing the screen paint mixes, I realized that the angular reflective properties provided by the metallic paints are less than the provided by the screen materials tested before. This is good news for me, since I got too much hotspot using the tested ALR materials. Another conclusion is that when using the white plastic paint (mix 2 and 3), the effects of the metallic paint disappear. However, for the mixes 1 and 4, the metallic paint provides good reflective properties for rejecting ambient light.

In the next days I will try to understand why the standard white mate plastic paint is not working with metallic paints and try other paints for mixing with the metallic ones. I would also like to try mixing metallic FolkArt with matte water-based poly (as the original FolkArt mix) despite it is not recommended for rolling.

Images
Find attached some images and graphs showing the results of the different tests.
* ScreenMaterials_ALR: Image shows the 5 tested screen materials from left to right: MaxWhite, ProWhite and ProGray from PSM and CineGrey3D and CineGrey 5D from Elite Screens. The projector is shown an image divided in white (up) and black (down).
* ScreenMaterials_DarkRoom: The same materials in a dark room
* PaintMixes_ALR: Testing the paint mixes from left to right (1, 2, 3 and 4) in ambient light room
* PaintMixes_DarkRoom: Testing paint mixes in dark room
* ALRoom: Graphic showing the results on Ambient Light Room. The screens with angular reflective properties have better blacks.
* DarkRoom: Graphic showing the results on Dark Room
* DarkRoomHotspot: Graphic showing the results of Hotspot. CineGrey 3D have a high hotspot at top left corner.



Paint references
* White Plastic Mate: https://www.pinturas-alp.com/producto/apolo-formula/
* FolkArt Gunmetal Gray: https://plaidonline.com/products/fol...etal-gray-2-oz
* FolkArt Medium Gray: https://plaidonline.com/products/fol...dium-gray-8-oz
* AutoAir Aluminium Base Fine: https://autoaircolors.com/custom-aut...aint/4101.html
Attached Thumbnails
Testing ALR Projector Screen paint-screenmaterials_alr.jpg  

Testing ALR Projector Screen paint-screenmaterials_darkroom.jpg  

Testing ALR Projector Screen paint-paintmixes_alr.jpg  

Testing ALR Projector Screen paint-paintmixes_darkroom.jpg  

Testing ALR Projector Screen paint-darkroomhotspot.png  

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Last edited by xplanes; 06-09-19 at 03:48 PM.
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alr , paint , projector , screen , testing

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