Join Date: Oct 2004
Location: Battleground, WA
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I have tried about 20 different mixes and combinations there of. What I have found is that pretty much everything has a trade off, even this current screen that I am going to talk about here has a trade off. The bottom line is that it is almost impossible to have your cake and eat it to with a diy screen. If you read and study TRYG's work as a primer (much respect for his hard work), I think you will find that this is a true statement. I realized without extensive development and or the proper tools and or suppliers a good 2.0 or higher screen that does not have major compromises is just too difficult.
In developing this next screen, my goals were:
- 1.5 to 2.0 gain
- Cheap under 50 bucks
- Keep It Simple (easy to do)
- Readily Available materials. (US)
- NO hotspotting (I can't stand hotspotting)
- Minimal Color shift
- Minimal Sparklies
- Will work well with both CRT and Digital projectors
Using those goals you can minimize a large number of the different combinations not based on white with the color shift. And most of the higher gain paints are going to have issues with hotspotting.
So where do I start.
I had recently gone back to Ultra Pure White Flat after many failed attempts. So I decided since this was what gave me the best overall performance I would use this as my base coat, and would start with it.
Next I went in to my workshop and started going through all the paints I had from previous attempts. At first I thought about trying another mix, and I realized that no matter what you do anytime you ad UPW to a mix it will cover the reflective elements and make the additive pretty much ineffective. The problem is I wanted to base the screen on UPW because I wanted to keep the colors in check.
I pondered for a few days and did a few tests to see what the results were. First thing I did was scrap any Idea of mixing the paints.
So that leaves me with on the option layering different paints to achieve my goals.
The next issue was well if I layer paints how could I keep the UPW as base without tinting it too much.
I ended up wanting to use translucent paints on top of my UPW base. So what do I have in the basement that meets that criterion? Well of course good ole WOP. However I have done probably 7 or 8 different wop mixes, and they almost all had sparklies. This may be an issue.
After doing a test sample, I decided to go for it. So I took my base UPW screen and painted a medium to heavy coat of WOP on top of it. I took great care to get it close to perfectly even after I applied the cote I went back over it lightly with out adding anymore paint to even it out and get it nice and textured.
I let this dry for 4 hours and turned on PV885pro CRT projector. Holy hotspot and sparkly craziness!
I thought that this was a showstopper, which I figured it would be. I just had never tried pure wop before. I did notice that the sparklies were only really prevalent in the hot spot and were very consistent. I studied the screen for a while to try and get an Idea of the color shift that the WOP caused. The wop really had some minimal color shift towards the blue, but the colors were much more vibrant and the whites almost blinding. So I decided I wanted to do a clear topcoat just to see what would happen I tested three. 2 of which I already had and the third I picked up at HD.
Here are the three combos I tried on samples (BASE COAT - MID COAT - TOPCOAT
1. UPW - WOP - Behr Light Base Flat
2. UPW - WOP - Flat Clear Gesso matte
3. UPW - WOP - Behr ultra Crystal Clear water based matte (I picked this one up)
The first combo was to dull and did not give enough gain and made the colors look dull to me. I discarded.
The Second combo was similar to the first it just seemed to take too much of the punch out. It is pretty thick stuff so maybe that was the issue. Nonetheless I discarded
The third gave me some unexpected results, I was expecting it to have the same effect but it didnâ€™t. It dried really smooth and most of the texture from the wop application was gone. When I held it up to the light I did not notice and individually sparklies, but I did notice that it had some weird properties in that it had the same look as the white on a road sigh just not as consistent. It did not hot spot at all and when held up to a UPW sample with no topcoats it had the same coloration but only brighter, at a 3 ft distance the sparkly undercoating was gone. I decided this was going to be the one.
I applied a healthy coat to my already painted UPW-WOP screen again taking great care and going back over it to even out the coat.
So the test of truthâ€¦â€¦
I let it dry overnight and hurried down the next morning to test it out. Flipped on the projector to let it warm up and ate breakfast.
About 15 mins later I went down ant started going through my AVIA test patterns. I was dumbfounded at the progress. The colors were natural the contrast was improved. I made a few adjustments to get the projector calibrated to the screen. I had to adjust the contrast as the darker areas of the picture were now to dark compared to the whites. I also lowered my brightness a hair. I also had to turn the blue down just a hair as I noticed a slight blue push very slight. The colors were much more vivid but not overpowering. I was geeked. I have an old radiant screen that has a gain of about 2.0 it was definitely as bright but because it was based on white it had much better coloration. The picture over all appeared shaper as the bleed that I got with just a UPW was now gone. I checked the viewing cone and there really didnâ€™t seem to be one till maybe the last few degrees adjacent, almost 90 degrees. I even can now watch sports with the lights on full.
I am very happy with this so far, 3 days and 5 movies later I really havenâ€™t been able to notice anything negative points to this screen.
After 1-Â½ years of experimenting I think I finally found the compromise I was looking for. I just canâ€™t believe how simple of a solution it was, after all those complicated mixes, mirrors, and multiple coated mixes. I think I have come close as I can get to my goals with a DIY project.
I am getting a digital projector this week so I will let you know how that goes. Proxima LX1 1078x720 native 300:1 contrast 800 lumens and a Nextvision N6 for HD tuning.
My list of materials:
I started with a 77x54 BOC screen (any screen will work)
1 â€“ Quart of Behr Ultra Pure White Flat wall Paint $6
1 â€“ Quart Behr Premium Plus White Opal Pearlesence No. 751 $19
1 â€“ Quart Behr Premium Plus Crystal-Clear Water Based Polyurethane Clear Matte No. 780 $15
Total cost of paint = $40
Simple Instructions â€“ Apply heavy even (or several light coats) coat of UPW with roller. Apply medium coat of WOP with a roller. Apply medium coat of CCM with roller let dry 4-6 hours between coatsâ€¦.Enjoy.
DISCLAIMER - These were my results under my conditions, and my evaluation of them.
As many of you have, I also have gotten pretty frustrated in the DIY screen fun, and I just wanted to share my results with all of you.