After discussing the situation with wbassett for several hours overnight I have decided to reword this post.

I will say that the aluminum is looking like a very promising replacement for the pearl medium in our attempts to create a high gain solution that may work for the folks here.

As far as mech goes . . . well mech is mech, but we him anyway.

Mean spiritedness starts within. Look inside Todd. I don't think anyone's said a mean thing here at all. Just showing actual data. I'll try and get the spectral curves for the Behr poly on Monday. They may have even changed a bit as they have 'aged'.

As for drumming up members? Who's taking shots yet again? That's all I'll say of that.... again. You don't think someone who built there own pj might want a free professional paint mix???

mech

I managed to negotiate a reprieve from the ban on testing, but only until I finish the final painting of my own retractable screen. I just painted the trial flat black border this weekend so that will have to cure and then get tested for a week or two. Then the final screen will take another three or four weeks. So that gives me some time to play around with a new carrier for the pearl and also get some of the Auto-Air Aluminum Base and see how it works in my applications.

If I hit on anything useful I will be sure to post it.

In the meantime if someone is going to try the pearlizing clear coat and they can get the Valspar Clear protector from Lowes instead of the Behr polyurethane I would be very interested to here how well it works with the pearlizing medium.

I need a little feedback before I do any further investigations.

What sort of sizes of screen do LumenLabers usually go for?

Given the low 200 lumen output of these projectors, is it safe to assume that people expect to use the screen in a darkened room?

Are these projectors likely to produce poor blacks?

I can answer these questions as they relate to me.

#1- I am right now, right around 117.5" diagonal.

#2- Yes, when watching anything, the theater is as dark as I can get it.

#3- As for my setup, I think mine produces pretty darn good blacks, but hey, I'm no trained professional, so they might not be as good as they really should.

The reason I am asking about the black levels is I am trying to determine what the most meaningful sample panels would be. Typically we are talking about low lumens in a dark room so a white screen seems appropriate. If the projectors tend to have poor blacks then a very light gray may help with that while some gain will help maintain the brightness.

So I guess the question that is really on my mind is if a matte white painted sample panel compared to various top coated matte panels is the most relevant or is a bit of gray needed to help with black levels.

OK, I think I have decided what I will do. The first thing we need is a reference. I want to use up and stretch some of what I have so my reference will be a matte white made up of some UPW mixed with some Glidden Gripper Primer. I will paint two panels with this, one for our basic matte white reference and one that I will apply a top coat over. For now I will refer to this top coat as SNOW. It is white and I expect it to boost the gain, so it will make a nice bright white screen. It is made up of very easily acquired products.

Now before I go on to the next samples panel let me show you some preliminary results:

On the left is a photo of a mix we will call FROST over a black poster board. On the right is a sample panel with a base coat of 0 12 0 LB /qt. This was a deliberate attempt to have a base coat that pushes blue. The interesting thing about the FROST is the underlying base coat seems to have less influence than one might expect. The background screen is a near neutral tint in Behr Ultra 4850 that only has 0 6 0 LB/qt plus some brown oxide and medium yellow. Note that is quite a bit lighter than the base layer of the FROST panel.


Click images to enlarge.

It is interesting just how white the shirt is in the first photo. Remember that is black poster board under the FROST. I done mean to mislead anyone though. The FROST over black is not as bright as either the FROST over 12LB or the background screen.



There may even be some blue push to the FROST over black.

The point that I wanted to make is that the FROST is able to really boost the brightness. Therefore I want to make sample panels that will take advantage of that and add some Lamp Black to the base. Not a lot though, just 0 2 0 or 0 4 0 LB/qt. Given how much brighter the FROST over 0 12 0 LB/qt is I expect to get more brightness than the white reference panel with some gains in the black as well. All the products used to make FROST are readily available from local retailers as well.

So the first lineup is:

1. - Matte White Reference (1 Part Glidden Gripper Primer + 1 Part Behr ULTRA UPW #4850)

2. - Matte White Reference + 2 coats of SNOW.

3. - Very Light Gray (0 3 0 LB/qt) + 2 coats of FROST.

When the Auto-Air Aluminum Base arrives I will determine a workable mix for a top coat and add an appropriate sample panel. At this point I have no idea what the base coat should be to compare to the matte white reference. I'm guessing it may be a fairly dark gray

Just a small update. I was not satisfied with the whiteness or the coverage of the 1:1 mix of Glidden Gripper Primer and Behr ULTRA UPW #4850. I added some more UPW such that the final mix was more like 1 part primer to 2 parts UPW. So far the two panels have 3 coats on them. The panel that will be our matte White reference will get one more coat. The other panel will get two coats of the mix that for now I will call SNOW. If all goes well this evening that application will be complete and tomorrow evening we will get a chance to compare the two.

SNOW (1 coat) vs Matte White

I was curious so I threw the SNOW sample panel in front of the projector. I was pleasantly surprised at the results.

Here is the SNOW and Matte White reference panel with room light and camera flash:

Click images to enlarge

The SNOW, on the left, is brighter than the matte white and showing no signs of hot spotting. For a frame of reference this is a very similar screen surface to Da-Lites Video Spectra material.

Here are the two panels under white light from the projector.

The off axis shows that at around 40 degrees the two panels have the same brightness. The SNOW panels then continues to drop off gently beyond that.

SNOW (1 coat) vs Matte White

Here are a few more on and off axis screen shots of the SNOW on the left and the Matte White on the right:

SNOW (1 coat) vs Matte White

Here are some flesh tone images:


Click images to enlarge.


And just a couple of random screen shots:




So far I am quite pleased. The SNOW top coat rolls on very nicely and as the screen shots show it is adding a nice gain boost without severely restricting the viewing cone.

Tomorrow evening I will present additional photos showing how 3 thin coats SNOW compares to the Matte White.

Two Roller Method For Applying Smooth Finishes

I should mention that for these higher gain applications I have been using a two roller method to get a very smooth finish. The amount of texture usually created by fuzzy roller will become very apparent in the image once higher gain top coatings are employed so I developed a modification of basic screen roller painting to take advantage of the strengths of the fuzzy roller and the 6" hard foam trim roller. The fuzzy rollers are great for getting paint on the screen. One roller load will usually be enough for one vertical strip. The 6" foam trim rollers are great at smoothing and in the case of metallic type paints down rolling. So here is a little demo of how I painted these panels:


Click image to run video.

It should be noted that when using this method it is necessary to thin the paint. If you try this with good old Behr UPW right out of the can it will not work so well. Adding about 15% water to the UPW will allow this sort of rolling method to be employed.

Here is a comparison of a surface just using the fuzzy roller and one that was applied using the two roller method:


Click image to enlarge.

Here is a macro photo of Behr ULTRA 4850 with 12.5% water added. This is 8 coats applied to a fresh white hardboard panel.


And finally some people here may remember RS-MaxxMudd. This is a sample of it applied using the two roller technique.



Once you watch the video I'm sure any of you who have painted ascreen with a roller will see that it really is not difficult to use this two roller technique and the macro photos speak for themselves. This is a very simple way to get results similar to spray painting, however I would encourage anyone interested in spray painting to look into it. Do a google search for the Wagner Control Spray or the Preval Spray Gun for some inexpensive options.

What Is SNOW?

Initially I did not want to provide any detail regarding what SNOW was because I did not want anyone to think it was a viable screen paint solution until we had done some trials and had a look at the results. Now that I know that it a reasonably easy to apply "base coat \ top coat" solution, and that it does indeed produce a brighter image than the matte white, I would be willing to disclose the ingredients, mixing, and application instructions. However, I should also warn that this is only the first of 5 recipes that I am currently investigating. The SNOW also had the lowest expectations for significant results and as yet has not been tried over a light gray base.

Since these trials are probably going to drag out over a few weeks, I am willing to pass on the information to anyone anxious to implement a screen now, provided you understand that within a few weeks a more effective solution may be presented. In it's defense and to it's credit, one advantage of the SNOW solution is that all the ingredients are available off the shelf from Home Depot, including a 16oz. quantity of matte black paint for painting the borders. The first thing to do is make sure your wall is in good shape and fairly smooth. Apply a good base of white primer and then keep watching to see which recipe will best suite you. If however you just want to get on with it, then send me a PM and I will tell you how to implement a SNOW DIY screen.

When all these trials are done, I will start a thread to present all the viable recipes. So far it looks like we have one I am pretty sure of, three that I am fairly sure will work well, if I can roll them, and one that I really don't have high expectations for.

As a follow up to this round of experimenting I may revisit the Behr Polyurethane #780 pearlizing clear coat approach and see if starting with a Lamp Black only base will result in a more neutral screen surface. I may run out of time, money, or energy by then so if anyone else wants to explore that idea please feel free to go ahead and don't hesitate to post or pm any questions about how to go about those trials.

Snow (3 coats) vs Matte White

Well this is a little disappointing. I really don't think the performance changed by applying the additional two coats. That would suggest that all the gain benefits are coming from the sheen and not the reflective particles in this top coat. It's not worse than with one coat but it does not seem to be much better. Therefore it is not a very cost effective solution.

Here are the room light and camera flash photos:

Click images to enlarge.

Here is the bright white light from the projector:

SNOW (3 coats) vs Matte White

It is brighter than the Matte White but I don't think any more than with just one coat.

Projected white light on SNOW (1 coat) to compare with photos in previous post.

I was hoping then that maybe the blacks would be deeper but I don't think so.


So I don't see the point in a mix that results in plenty of top coat for 3 coats and costs $17 more to do it. The only real benefit is the fact that all the materials are available at Home Depot.

SNOW (3 coats) vs Matte White

And now some screen shots to look at:

SNOW (3 coats) vs Matte White

More screen shots:

SNOW (3 coats) vs Matte White


An a couple more screen shots for good measure:

Just wondering if someone's tried projecting onto a piece of wood painted black.

I tried applying a pearlizing clear coat over a piece of black poster board.






The interesting thing was that it seemed to do as well off axis as on. The blacks do seem to be pushing blue though. I think black may have been too drastic. A dark gray like N7 or N6 may be more reasonable.

It occurred to me that someone might wonder why bother painting the white hardboard white if it is already white. So I applied two coats of the SNOW top coat directly on the Cutler White hardboard panel. It applied very well and smoothed out perfectly. However it did not produce a nice white screen surface similar to the SNOW over Matte White. It was visibly darker and yet it did not seem to produce any better black levels. So I would conclude that the Behr UPW white base is well worth the effort and cost.

Tonight we mix up and apply CRYSTAL. This one I expect will do fairly well. Tomorrow we will see if it lives up to my expectations.

Here is a sneak peek at the white sample panels:


Click images to enlarge.



First Impressions

The FROST sample has a brownish red cast to it. I suspected that was going to be the case due to the lack of clarity in it's base medium. The CRYSTAL (2:1) is very bright but alas it also was not possible to roll it without streaks. It does however seem that the CRYSTAL can be sprayed with good results. The SNOW actually appears to be the winner of the Matte White round.

There is a third contender that I am anxiously awaiting the arrival of. I just got notice that it was shipped so it should be here next week.

While the SNOW appears to be better than the plain matte white I am not sure it warrants the added expense. In fact you may get just a good result by mixing a quart of Behr ULTRA Flat #4850 with a quart of Behr ULTRA Satin #9850.

The next step is to see what kind of results we get when applying these top coats over a simple gray made up of 0 3 0 LB/qt of Behr UPW. Using a light gray base is intended to deepen the blacks while the top coat will hopefully keep the whites bright. I plan on only a simple gray that may push blue slightly so that the tendency of the top coats to has a brownish red push will balance it out.

Update

The previous work with various clear coats over a white base may have seemed fruitless but indeed it did lead to some further understanding. The Folkart Pearlizing Medium is comprised of a semi-clear base with very small mica flakes in it. It turns out that not only was the Behr Polyurethane #780 adding an amber filtering effect to the clear coat, the Folkart Pearlizing Medium's base is a brownish color as well. The result was that the FROST which was a mixture of the Folkart Pearlizining Medium and a better carrier than poly was quite brown in appearance. In fact off axis where the mica is less significant it looked almost redish in color.

The other two mixes CRYSTAL and SNOW were both much whiter. So at this point I have basically rejected the Folkart Pearlizing Medium, but the other two sources of reflective particles are still being explored. The materials for CRYSTAL and SNOW are easily acquired locally in most cities and towns in North America. I am awaiting some Aluminum Base to make up some samples and do some apples to apples comparisons. The Auto-Air Aluminum Base Fine may not be locally available to many people but it is easily acquired online. I fully expect to find the aluminum reflective particles to be quite effective, so at the moment I can see three new solutions coming out of this with various performance characteristics as well as component availability and easy of application.

I am currently performing some trials of these clear coats over a neutral gray base paint. Both the CRYSTAL and SNOW do not seem to be introducing and visible color shifts however the CRYSTAL is going to produce higher gains but with the usual reduction in viewing cone. I am currently working with a (3:1) CRYSTAL with which I was able to roll a very uniform coat. This has encouraged me to revisit the the CRYSTAL over a matte white to see if I was just not paying enough attention the first time around. Aside from the streaks the CRYSTAL over matte white was quite encouraging as a higher gain white screen solution. At that time I will also re-evaluate the SNOW over a matte white base.

Soon I will post some photos that show how well the CRYSTAL and SNOW perform as clear coats over an ~N8 neutral gray base. They will be compared to just the flat gray base which is really not very meaningful except to see if there is any significant color shift. I have also made up a panel with a 2:1 mix of the neutral gray and some UPW. This is to address the usual question of why not just use a lighter gray. I will also make up a sample panel with just the carrier to see if that is actually what is causing the gain change.

There are others quietly working on these solutions as well as looking into the use of aluminum flakes and reporting some very interesting results. The current climate in the forums has driven some of us underground for the time being but I am confident that that will soon change.

Stay tuned . . . the mixers, rollers, and sprayers are humming away underground.

I forgot to mention that I will also try the aluminum in the base gray but this thread is really about gain boosting clear coats. By mixing metallic or pearl flakes in an opaque base I think you are wasting their potential so I will leave that sort of development to others, but I must admit I am curious. Ostensibly my interest is in seeing the effect on gain and viewing cone. I'll leave the color balancing work to those who have the equipment to do it. Color balancing to get the overall color back to a neutral gray may not always be easy or intuitive, but it is always doable one way or another.

Tiddler, really enjoy lurking on your thread. Just wanted you to know someone read all this stuff and followed it.

If I am reading right, the goal is to find a clearcoat that one can apply over a base (UPW or whatever) that will generate a gain and narrowing of cone to some degree. Basically then, to find something between a flat white wall and a Dalite High Power?

Yes that is the basic idea. The original Pearlizing Clear Coat was Behr Polyurethane #780 with some Folkart Pearlizing Medium mixed in. The poly itself is adding an amber filtering effect and the pearlizing medium turns out to have a brownish base as well. The end result was that the overal color balance was pushing red. It may be possible to counter that by modifying the base layer to have a blue push that when coupled with the top coat's red push the whole thin balances but . . . The problem is the number and thickness of the clear coats will change that balance. So I am now looking for a clear coat that introduces as little color shifting as possible to start with.

As you say the end result is that more light is reflected back toward the viewing area and less off to the side. At the same time you don't want to introduce significant first surface sheen because that usually leads to hot spotting. That may not be as big a problem with projectors in the 200 Lumen range though.

So far I have found an alternate to the polyurethane that is very readily available. I just got off the phone with the head of the manufacturer's laboratories and they indicated that this product should be stable over the long run (ie 5-10 years). A lot depends on the amount of UV exposure for most materials. I have also been directed to some cleaner sources of pearl and other reflective flakes so things are progressing in the right direction.

In the case of the folks here a good white base may be the best option but a very light gray can be used such that with the added gain of the top coat you get whites comparable to a good white screen and darker blacks. The aluminum base that the folks at HTS have identified Auto-Air Aluminum Base Fine is likely to be a superior reflective particle to the micas but may have it's own color shifting issues. Keep your fingers crossed!

Just a quick update . . .

The CRYSTAL over gray base was a complete disappointment. It was not really any different than the gray base by itself.

The SNOW did much better but it appears to have a fairly narrow viewing cone. Maybe 30 degrees off axis it is producing a similar image to the light gray reference panel.

I don't have a lot of time tonight so here is a link to the photo set.

Well if nothing else this is preparing me to be completely dazzled by the aluminum base when it finally arrives.

I received the Auto-Air Aluminum Base Fine yesterday. It was left on my front step and was partially frozen when I got home from work. It seem to be ok though.

I tried a few quick trials in my current top coat applications. It took a bit of getting used to how strong this stuff is. I had to keep diluting the top coat down and I still have a very dark gray but the results are interesting if not promising. In these photos the outstanding thing is how black the blacks are. These were taken with a 60 watt lamp in the back corner.

These white projected light shots demonstrate how dark the sample panels is:



Yes, there are a few streaks but this is too high a concentration so that's not surprising.



I was most struck by the darkness of the blacks in these shots.
This of course came at a cost of the white levels.

There may also be a bit of a blue push. At least the photos seem to be showing that. I think it may be my camera though. Originally people were suggesting there was a blue push with the Pearlizing Clear Coat but when they got a spectro and measured it they discovered there was actually a red push. The Behr Polyurethane #780 red push may just be the ideal counter partner for the AAA blue push. We shall see.
A blue push would be consistent with the problems others have had when mixing the AAA in a base paint also, so no big surprise.

Here are a few lighter scenes:



Naturally the whites are somewhat darker than my own screen. That comes as no surprise though.

Again the black levels were most improved.


Not bad and certainly quite encouraging for a first few trials as part of a clear coat.

Of course when Mech gets the Base+AAA worked out I will give that a try and throw up some screen shot comparisons. That is assuming the base is fairly easy to come by. If it is a Lowes exclusive then I won't be able to try it.

I have come to the conclusion that due to the fact that the aluminum acts more like a pigment when embedded in the paint, even a fairly translucent film like ULTRA deep base or the polyurethane, and only acts like a reflective particle when right at the surface, it is not really useful as clear coat component. This was also confirmed by an experiment that mech performed. He applied a flat clear coat over a paint that had an aluminum paint mixed in it. The result was that the surface acted like it had just been painted with a dark gray flat paint.

For clear coats with embedded reflective particles I really think the pearl type flakes are the way to go if at all.

The next step is to try to do an apples to apples comparison. I have some UPW with just lamp black in it. I have tried to match a mix of the Auto-Air Aluminum Base Fine with it. No this is not a neutral gray. At this point that is not an issue. The question I want to address is does the aluminum make for a better way to add gain. So once I have a very similar shade of blue gray for each I will then add 25-30% satin polyurethane to the Lamp Black tinted UPW and then compare the two panels. This type of comparison has not been done as far as I know. So far I have only seen the aluminum based mixes compared to matte gray paint. The other interesting comparison would be a gray created by adding a silver metallic paint to a base. This will also result in surface sparkly bits just like the aluminum based paint does.

Unfortunately none of this is likely to lead to a screen suitable for lower lumen projectors. In order to get enough sparkly aluminum bits on the surface you need to add enough that you end up with a pretty dark gray like an RGB of 182 183 183. For the low lumen crowd the best hope will be in what may be possible with a spray gun.

It has occurred to me that an investigation of gray screens and various gain boosting methods is really not appropriate to the low lumen crowd here at Lumen Lab. I have encouraged a colleague who is also investigating similar top coats applied by spray painting, to pass on any discoveries that may be of interest to the low lumen crowd. Spray painting will allow higher concentrations of pearls and aluminum while still being able to produce a uniform coating.

For anyone interested in my ongoing experimentation, I have begun a comparison of the known gain boosting ingredients that are added to paint mixes. This is not pearl clear coat related work but will include some comparison of mixes that include iridescent mediums.

So, Tiddler ... bottom-line time:

1) Among all the options of simple base+topcoat applications, what have you found gives the best gain while maintaining a strong white approach, which should be best for what we do?

2) Are there maybe 2 or 3 top contenders now in terms of gain without hotspot that rise to the top and should be racehorsed against each other?

3) And what, if anything, would you recommend buying now for a screen?

The only thing I have played with lately that really impressed me was the SNOW top coat over a white base. It added some gain without going too far and killing the viewing cone. It was easy to roll and get a very nice smooth finish using the two roller method.

There really was not anything else that struck me as being better than a good matte white base. By matte I mean either Behr ULTRA UPW 4850 or the Flat Enamel UPW 1850. The Behr UPW #1050 is too flat. Applying a top coat of the SNOW gave it a further bump in gain and did not appear to hot spot or shift the colors.

It pulled the Matte White sample panel and the Matte White with a SNOW top coat out and took some more comparison photos.

Click here to see the complete photo set.


The SNOW is a very simple top coat made up of one 16oz. bottle of Behr White Opal Pearescent #751 (WOP) mixed with 16oz. of Behr Premium Plus Ultra™ Exterior Flat #4853 Deep Base (UDB) and 6oz. of water. I applied it using the two roller method. I used the 6oz. of water to rinse out the WOP bottle. I usually apply two coats of any paint or top coat just to be sure of proper coverage.

This did brighten the on axis image but like all gain boosting there is a penalty in off axis brightness. This is demonstrated in the photos showing white light projected on the two sample panels.



Click images to enlarge.

It is quite likely that adding some satin polyurethane to the gray paint would have an equal effect on gains as might just mixing the Flat ULTRA with some satin ULTRA.

I took several photos just off to the side of my living room and about 10 ft from the screen. This is really the worst place anyone might sit in my room. These show that the worst a guest might see is the same performance as a matte white screen.





Even Bruce does not look too bad off axis.


I am not advocating or recommending this type of top coat but just answering the questions from weldnjb.

There are three basic ways to improve on a matte white Behr ULTRA 4850 screen. Add some Minnwaxx Clear Satin Polyurethane to add some sheen. Mix ULTRA Flat and Satin to get an increase in sheen. Or apply this sort of top coat. The nice thing is all the products are available at Home Depot. In the case of the SNOW you will have 16oz. of ULTRA Deep Base left over. You can take the can back to Home Depot and have them put an ounce or two of Lamp Black in it to use for the border. I have also found the ULTRA Deep Base is excellent for sealing masking tape edges.

I should add a thank you to benven. He is a member over at AVS that put me back on to try some things with the WOP. He indicated that it was the whitest of all the pearls he had tried. That is why I decided to try it in a top coat using the Behr ULTRA Deep Base. I have also been in touch with the Behr Color Laboratory and they indicated that the Behr ULTRA Deep Base would have all the advertised attributes of the ULTRA line of paints regardless of whether any tint was added to it or not.

I personally have no problem with bringing the cone down in size for a boost in gain. For your typical room, it seems like the cone will be small anyway. i know for my setup, I would have no issues with going with a Dalite High Power style cone.

Hi tiddler,
Went to Wal-Mart and could only find (FolkArt 659 Metallic Pear White).
The sample color Dot that is on the top of the bottle looks very tan/gold looking as dose the paint looking at it through the plastic bottle? Is this the right stuff ?

I don't really recommend the Folkart Pearlizing Medium and Behr Polyurethane anymore. The combination introduces a red shift to the color balance of the screen.

What have you done so far?

Have you purchased the Behr polyurethane yet?

Your fast tiddler,
Nope, I have done no painting yet I just got back from Wal-Mart so I only have the FolkArt and the sales slip so it sounds like I should return it ? Right ?


So what should I buy ?

Yes unfortunately you should return it.

I assume you have a low lumen projector and you were going to use a white screen with a pearlizing top coat?

That is right Sir.

The best painted option I am familiar with at the moment is the Behr Premium Plus Ultra™ Exterior Flat #4850 without any tint, so it is just very white paint. From there I can think of two options.

The first option will allow you to tailer the sheen to your projector. get a quart of the Flat ULTRA 4850 and a can of the Satin ULTRA 9850. Start with one coat of the satin and let it dry completely for about 5 hrs. If you don't get hot spotting then that is the sheen you want. In that case return the quart of Flat ULTRA 4850. If you do get hot spotting then try a mix of 1 part flat to 3 parts satin. then 1:1, 3:2, then 4:1. If you get down to just wanting the flat ULTRA then you will have wasted some money to find out that no one else should try the satin. I doubt that will be the case though.

Here is a video on how to paint the screen with the ULTRA paint:


The other option would be to go with the SNOW top coat that I described starting at this post. I have no idea if it would be better than the first option, and I suspect the first option is a little more forgiving of roller painting skills. So I offer it to you only to be complete. It will also cost more than the first option to buy the paint.

Here is a video on how to apply something like the SNOW top coat:


In the end I suspect the first option is the easiest and it will allow you to dial in the perfect sheen for your setup.

I should also point out that the Behr ULTRA paints are self-priming, very durable, and UV resistant. They also happen to be very flexible to withstand the expansion and contraction due to temperature changes out side. All and all a very durable paint product that make a good screen paint.

Thank You very much tiddler,
I will give option #1 a Go.
What nap roller do you use ? 1/4inch?
Is there any other info I need to know about which roller to buy other than nap lenght ?

You should try to find a 3/16" nap roller but the 1/4" will do. Get the best quality white synthetic lint free roller they have. You may not be able to find a 3/16" roller but do not go any thicker than 1/4" nap.

It's people like you tiddler that make the internet worth a dam.
You take the time out of your life to teach your skill to someone else that needs it. Thanks.
Great videos.
Anyone can buy paint and a roller and slop it on a wall..That is not what tiddler is showing us how to do. That screen in the back of the second video looks like a work of Art.

Thank you for the kind words.

That screen in the background is a retractable. My pet project was to figure out if and how to paint a retractable screen. There are a lot of people that get a white screen not realizing it will not work so well in a room with ambient light. In many cases the screens are free with the projector as a package deal. This new Behr ULTRA paint has made it possible for me to develop a technique for painting a retractable using a roller and a minimal amount of paint.

I should also mention that mech is going to be working on some super white screen paints.
You should keep an eye on his Black Widow thread for some future developments.

Excellent videos!

Tiddler, do you think .8mm micro beads might help in the mix? Seems like I have seen some testing somewhere on this, but maybe not. They also have flakes and glitter.

There is a member at AVS named "bruce can" who has done a lot of work with glass beads in the past. I will try to contact him and ask him to join in here and pass on what he knows about making retro-reflective screens.

Tiddler, I don't want to derail the thread, but do you have knowledge of any newer discussions regarding rear projection materials/topcoats for viewing an image on both sides (DIY wise that is)? High thread count sheets work amazingly well in my opinion, but it seems like some kind of topcoat to either side once stretched would be an improvement. Either that or a rigid piece of plexi with a top coat.