Hi,
After days of research on the net, I choose to paint my screen wall with the behr flat upw #1050 with behr polyurethane clear #780 top-coated...Only one question bugs me..Should I mix the #1050 with some #751 behr pearlescent clear? Will it result in a appreciated gain or will it be too much or is it completly a bad idea??

Thanks!!!

While it is true that a top coat of Behr Matte Polyurethane was at one time recommended, it was found to introduce an amber filtering effect that resulted in the screen surface not being neutral. Therefore I no longer recommend it's use.

The good news is that adding some of the behr WOP to the flat behr UPW #1050 will result is an excellent white screen. Therefore if you can return the Behr Matte poly and get a 16oz. bottle of Behr White Opal Pearlescence (WOP) #751 you will be much better off.



Mix the a quart of the UPW 1050 with the 16oz. bottle of WOP. That is a a 2:1 mix ratio. I also like to use 4-6oz. of cool water to rinse out the WOP bottle. Add this rinse water to the mix as well. Be sure to stir the mix really well with a drill attachment type stirring tool.

Then simply apply the paint according to the following demo video, using a good quality low nap roll. Get a 3/16" nap roller if you can find it. A 1/4" nap roller will do if you can't find the 3/16".

Thanks for your help!

How much coats of #1050 and #751 mix should i paint for the best results?
A quart of #1050 will be enough for the job?

A quart of paint is usually just enough for two coats on a 120" 16x9 screen. With the WOP added you will have 1.5 quarts of mix.

Typically two coats of paint over a good white primed base layer is enough. If the wall is not already white then a couple of coats of white primer like Kilz2 is usually recommended. Any white primer will do in this case since the top coats are also white.

Be sure to bag the roller between coats. Just roll it up in a plastic bag. I found plastic grocery bags or small garbage bags work well.

If you have not already purchased any paint then I would like to suggest n alternative.

Instead of the Behr UPW Flat #1050 + WOP, get the Behr ULTRA Exterior UPW #4850. The 4850 is self priming and it levels out to a very smooth finish.

Here are a couple of comparison photographs from the Bright White Behr 4850 thread.

ULTRA 4850 ~vs~ (2:1) UPW 1050 + WOP


Now if you go with the behr ULTRA 4850 and feel that you must added something to make it a screen paint, then add 8-10oz. of Minwax Satin Polycrylic to a quart of the Behr ULTRA 4850. The satin polycrylic will increase the gloss slightly and also help the 4850 to level out to a glass smooth finish (assuming a smooth surface to begin with).


And just to show the benefits of adding WOP to the 1050 if you are going that route . . .

(2:1) UPW 1050 + WOP ~vs~ UPW 1050



Either way, 4850+Satin Polycrylic or 1050+WOP, you will have a nice bright white screen.
The main benefit to the 4850 and the 4850+Poly is the way it levels out to a very smooth finish. This may not be so important with lower resolution projectors but it can make a big difference with a 1080p projector shooting a 120" image size.

Thanks very much!
I'll go with the bEHR 1050+WOP, with a little sanding on the wall and a good primer. I'm very confident! And i don't have to pay 250$ for the goo system..(what i did in my first house!)

I'll send pics and comments when it's done!


thanks again!

Sounds good!

We will look forward to seeing your photos.

What projector do you have?

What size of screen are you making?

What color are the walls and ceiling in your room?

Ok!!! (excuse if my english is not so good, i'm talking french..)
The work is done! I'm very very happy...
For my untrained eyes, it looks like identical to Goo System! 2 coats of primer, 2 coats of #1050 and WOP...that's it!

I own the Optoma H31, dvd->components cable tv->S-video (the tv is not HD for now)... The sound system is very basic but plays clearly...the only problem with the sound is that i've install my speakers too high...rookie mistake!

I'm very happy with my setup...but something wrong with my projector...i realized that when there's a white background like snow, hockey game etc. I have bizzare "rainbow" colors and hair-like cracks on the screen. I clean the lens with a lens cloth nothing changed. If you have an idea what is it ...

here's some pics.!
thanks!

Is it possible you are seeing the rainbow effect that some people see with DLP projectors?

Don't know...
Do you think it can be the lamp?? I'm at 1980 hours (always in low mode)

If you have another very bright white light source, try shining that on the screen. Just to be sure it is not the screen somehow introducing these colors etc.

To reach a wider audience and therefore have more luck in getting some help, I would suggest you go to the Digital Projectors - Under $3,000 USD MSRP over at AVS. There should be some other owners of that projector who can help you get to the bottom of the problem.

I could not find an official Optoma H31 thread so just start a thread with a title like "Optoma H31 Problems Please Help!". I'm sure will get some H31 owners offering some help.

hyass,

Just wondering if you managed to figure out what is going on with your projector?

I'll open the case, remove the lamp and try to clean the light path (vacuum). The technician i spoke today, told me that I should have cleaned it frequently, he's pretty sure that dust have compromise the lamp performance...
Anyway, i'll try it before sending it to a repair shop ($$$$) ;(

Do you have numbers for this? On one hand you say polyurethane causes a color shift. And then you recommend WOP which doesn't?

WOP seemed to be the most prismatic of the micas from what I recall. I wonder what kind of rainbow effect it is you're seeing here?

mech

I was basing my comments on the results that could be expected by mixing some WOP with Behr 1050 on reports from other people who have actually trid some of these things and reported on their results.

No I don't have numbers for a mix of the WOP with Behr 1050. I also do not generally recommend that mixture either. The only mixture I recommend the WOP for is with the behr 1050 tinted Silverscreen. I do have numbers for that. That of course would not be a sensible option for a lower lumen projector though.

However I do have some proper comparison photographs of the 1050 + WOP next to the Behr 4850. In my opinion the behr 4850 produced a superior white screen surface. But you also have your objections to that also. You will see there is a Whibal card in the image so you can easily color balance the photograph and determine an approximate color balance for the WOP + ehr 1050. You also have RGB numbers for the Behr 4850 that you could cross check it with.

I no longer recommend top coating with the polyurethanes as they do introduce an amber filtering effect that causes a general warm push to the image. How much effect the polyurethane has when mixed into the paint is also unmeasured unless that information is also being horded now. You have the spectrometer and claim to have done all these experiments yourself so you must have numbers tucked away somewhere, right!?

According to wbassett, as we get closer to white with a screen surface the need for a true neutral color balance is less critical. Was he wrong in posting that?

If you have a better solution for a DIY painted white screen, I and everyone here would be eager to hear about it and see your data since you have all the equipment to make such measurements.

I'll give it a whirl when I get the chance. But my hunch is that WOP would cause problems. Who knows though? You could be right.

As for the polyurethane, you can just say that it yellows over time.

I'd stick to a basic indoor white latex paint in a matte finish for now. Dulux actually has something that's a dead neutral white in New Zealand. But I haven't looked for any here. And I have yet to see any paint expert recommend an exterior paint indoors.

mech

All paint yellows over time from what I have read. The Behr ULTRA Exterior 4850 is specifically formulated to have superior UV resistance and therefore will take much longer to discolor than most exterior paints let alone any interior paints.

The purpose in adding the Minwax Clear Satin Polycrylic is two fold. First and foremost it significantly increases the paint's ability to level out to a very smooth finish. Paints that normally result in a very rough roller textured surface will level out to a smooth surface with about 25% Minwax Satin Polycrylic added. Secondly the satin polycrylic provides a way to control the surface sheen/gloss. The Behr 4850 has many attributes that make it superior to most paints but one that is immediately apparent is the ability to level out to a smooth finish. If using the Minwax Satin Polycrylic is something you wish to avoid, then the gloss can be varied by mixing the Behr ULTRA Exterior Flat 4850 with some of the Behr ULTRA Exterior Satin 9850.

I have yet to see any paint experts make any comments regarding the use of exterior paints for small interior areas such as that required for a 120" projection screen. I have however consulted directly with a paint expert at Behr and was assured that using Behr 4850 exterior paint indoors was no different than using their bath and kitchen paints which also contain anti fungal ingredients.

A 120" screen with three coats is the equivalent of a 16.5 foot wall 8 feet high being painted. Hardly a small area. As for contacting Behr, why did they tell me ten minutes ago to not use an exterior paint indoors? They said that the big difference between indoor and outdoor paints is the amount of harmful VOC's in the paint - more in an exterior paint - much more.

I wonder why the world is changing to low VOC paint....



mech

Yes if you call the help line for Behr paints or any other paint brand you will get the stock answers regarding the use of exterior paints indoors. So you have demonstrated your ability to dial a phone and the ability of a "tech rep" to read the stock answers off of a card pinned to the wall of their cubicle. I contacted someone working in the Behr Laboratory in California and asked the same question, however I posed the question in proper context. I got a very different answer. So folks can decide to take the answer of a phone center "tech rep" or the head of of the laboratory.
Otherwise we are

As far as your math goes, a 120" 16x9 screen has an area of under 44 square feet. A room 10'x10x8' has an interior surface area (not including the floor) of 420 square feet, and that's a pretty small room. So of course the off gassing in such a room would be 10 times that of the 120" 16x9 screen area.

I have stated several times that the general rule is that you should not use exterior paints indoors. I would imagine there is a similar rule about using automotive paints indoors. Just like they recommend you only spray paint in a well ventilated area. A little common sense and some thought goes a long way. Unfortunately spite and personal disfavor can also go a long way but I am not prepared to continue this pointless argument any further.

There are plenty of alternatives to using the Behr 4850 exterior paint if you are not painting a retractable screen. If you are painting a retractable screen or any other flexible substrate, Behr Ultra Exterior 4850 paint has many attributes that make it one of only two paints I would recommend. The other is the Valspar Duramax Exterior paint. But this is way off topic as well. If anyone is interested in painting a retractable screen or BOC please send me a PM and I will start a thread to deal with that topic.




Behr interior Flat Enamel would be a good (safe) choice and any leveling issues are eliminated by adding 25% Minwax Satin Polyurethane. Another good option would be the Valspar Flat Enamel with 25% - 33% Minwax Satin Polyurethane added.

The use of Behr flat UPW #1050 or it's cousin Behr Flat Enamel #1850 are more relevant to this thread. The addition of WOP is not something I would recommend but it has been tried by several people who have reported good results. Another way to boost the gain of these paints is to mix them with Minwax Satin Polycrylic. I would recommend a mix ratio of 3:1 for the 1050 and 4:1 for the 1850.

For what it's worth I will be trying the Behr 7850 UPW. The bathroom ceiling needs painting so I picked up a quart of this Behr Ultra Pure White paint for Kitchens & Bathrooms. I should have enough leftover to make up a screen sample panel or two. The lowest sheen that it comes in is called Sateen Luster. I suspect it will have too much sheen, but maybe not. This is a nanotech product similar to the 4850. If it levels and performs as well as the 4850, maybe that will put this whole exterior paint issue to bed once and for all.

I finally got around to painting up a small sample of the Behr UPW 7850. If it were any other brand they would call it a semi-gloss. Therefore it is too glossy to use as a screen paint. It should be good on the bathroom ceiling though.