First-timer DIY Screen

[xflapx]

Hello. First let me say I love these forums, lots of great information.

I've spent the last few days talking with Harpmaker regarding paint mixes and the general process of setting up a home theater projector. I've settled on BW and was trying to figure out what to use as a substrate. I want to have the possibility of building something larger than 100" diagonal so my original idea of using hardboard limits me to just that. I'm going to be hanging it from a wall in a rented home using a french cleat, so it can't be so heavy it requires extensive alterations. Harp suggested I look into vinyl sheet flooring so I called around town. I actually found 6'x9' precut vinyl sheets from Lowe's for $30. That's about 55 cents a sq ft, though granted with a 4" border you can only turn than into a 115" diagonal 16:9 screen. Still it's not a bad deal and about 2 dollars a sq ft cheaper than quotes I received from the flooring stores in my area. In fact most of them told me there would be a 65 dollar freight charge for such a small order, since they kept nothing in stock that wasn't intended for a job. So, with that in mind, does anyone have a better/cheaper idea for a 100-120" substrate that is sturdy and proven?

I tried to post a link but i'm not allowed to yet. It's domco 6' precut white sheet vinyl from Lowe's. Model #L90216X9

I'm going to take a look at the back side over the weekend to confirm it's quality, until then any suggestions would be greatly appreciated.

Darin

[Harpmaker]

Hi Darin!

Welcome to the Shack!

If you haven't already found the thread about the vinyl flooring screen here it is:
http://www.hometheatershack.com/foru...ow-flavor.html

Quantum had better luck with flooring from Home Depot rather than Lowe's, but the test he used to determine this was a severe one. It is still something to think about if you have a Home Depot near you.

Peruse away, and don't be shy about asking questions.

[mechman]

Welcome Darin! You paint the backside of this right? I want pictures along the way!

[xflapx]

Thanks for the welcome.

I'm still going to check out the domco, as it only comes in 6x9 precut sheets. This isn't cut-to-order rolls like what Quantum tested (in fact I doubt I could even get a sample without purchasing the roll). Most likely the backside won't be the highest quality, but then again maybe I'll get lucky. I'm also going to head over to the new house (I'm moving in next week) to get the exact dimensions of the room. I remember thinking it was huge, but I'm not sure I can base screen size, viewing distance, and PJ throw distance based on "huge." Maybe it is smaller than I think and I'll be forced to build a 90" screen. this project is becoming more and more expensive...

[xflapx]

Just so this whole process makes more sense, let me first say I'm a student at UF. As such, money does not flow freely from the money tree. I had about 1000 dollars that my ex-girlfriend owed me for school and other things while we lived together, so she basically said "spend a grand on my credit card." While it's not free money by any means, it's not money lost as I never imagined she would have wanted to pay me back, so I thought I'd try to build a home theater setup for around 1000 dollars. I have the surround sound system and a HTPC, so all I have to do is focus on the visuals. I bought a Sanyo PLV-Z60 for around 750 assuming that the highest rated projector on projector central in my price range was the way to go. I didn't realize all of the mitigating factors at the time, but obviously at this point it's water under the bridge. It has a beautiful picture and I have no regrets. So with all of that in mind, I have a budget of about 250 dollars start to finish.

The room measures 18'x13'. The ceiling is 8' high. If I set one couch at 10' and one couch at 14', the suggested screen size according to SMPTE standards is 100". THX is 115", but I don't think I can pull off a decent screen that size at the budget I'm setting for the project. The domco sheet vinyl was very thin and the paper felt very chalky and weak, I'm 99% sure it would have reacted poorly to paint.

I can get very close to 100" diagonal if I use a 4x8 piece of hardboard and glue it to a frame. I can then attach a french cleat to the frame and border the hardboard substrate with velvet-wrapped mdf trim. It shouldn't be too heavy and will eliminate the concerns of a flimsy surface. As long as I'm picky about the piece of hardboard I feel confident I can make it work, and for less than 120 dollars including paint, frame, trim and velvet. I had planned on building a 10" riser to set the second couch on, but as it turns out the previous tenants are leaving a bar behind that they built. With a few alterations I can turn it into the riser at the cost of some 2x4's.

After completing screen, I would like to purchase a large quantity of black velvet to curtain off the back side of the room since it has an open doorway that leads to the kitchen and on the other side a door that leads to the garage. Also against that rear wall are windowed double doors leading to the backyard (the 18' depth was measured to the start of the kitchen opening, the room is actually 22" front to back). So the curtains would control the ambient light those doors and open areas create as well as allow a hall of sorts that would lead to any of those entrances/exits.

I'm going to be painting the ceiling a dark flat brown that matches the wood paneling on the walls, so all in all it should be a relatively light-controlled setup. Still I want the option to be able to open the curtains and throw a gameday party or whatever.

Now that I've explained my plans and situation to date I have a few questions. The bar, as it is, sits about 24" off the ground (once I lay it down to act as the riser), so I can cut it down to any height under 24", what do you recommend? Do you foresee any problems with my design? Do I need to ceiling mount my projector? What are the advantages of doing so?

Well if you made it this far thanks for reading, and if you plan on answering some questions thanks for being patient. I can't wait to start.

Darin

[mechman]

Darin,

You'd need an extra inch in height for a 100" screen - 49"X87". Or were you saying that you were attaching the linoleum to the hardboard?

I would cut the riser down to 8 or 10 inches.

As for mounting the projector, I'd try to put it on a shelf if you can. Ceiling mounts are not cheap and will put a dent into what's left of your budget.

[xflapx]

I said I could get close to 100", or I guess I should have phrased it "I can get close to the SMPTE standard for my viewing distance." I think I'm going to settle with a 90" screen. That way I can attach a 1x2 inch frame to the hardboard, screw the french cleat into it, add the velvet trim and call it a day. Then I don't have to worry about damaged corners or edges, and the cuts don't have to be perfectly clean. I found the 16oz bottle of AAA-F for 30 dollars shipped, so I went ahead and ordered it. The plush velvet is also on it's way, so all I have to do is pick up the materials from HD and Lowe's and I'll be ready to start next weekend.

There isn't a place to shelf the projector since the back of the room is open. In fact considering the dimensions of the room I have to ceiling mount it. It's either that or put it in the lap of the person sitting front center. Guess it wouldn't pay to arrive late to the theater at home either...

Oh and I called the current tenants again (how I originally go the dimensions of the room) just to make sure, and it turns out I have a terrible memory. The walls are drywall, not paneling. Looks like I'll have a lot of painting to do...

[xflapx]

Do you think there will be a difference between a single coat of BW over 2 coats of kilz prem and 2 coats of BW over 2 coats of kilz prem? Wouldn't there be a chance of the white having an effect on the projected image with only one coat? If so would a black primer have an opposite effect? What about a higher density of AAA-F in a base coat and a lower density in a topcoat? I can't seem to find much in the realm of layer testing. What about wet sanding? How does that effect the performance of a mixture? I've lapped several cpu's as well as worked with some acrylic that has given me reason to have some high grit sand paper at hand. The highest grit (can't remember number and it's packed away) gave my copper heatsink a mirror finish. Would wet sanding increase the chance for hotspotting, or is there a chance it would help to reduce any imperfections that result from rolling?

The development section has me thinking too much. I can't afford another obsession.

[Harpmaker]

xflapx wrote:

Do you think there will be a difference between a single coat of BW over 2 coats of kilz prem and 2 coats of BW over 2 coats of kilz prem? Wouldn't there be a chance of the white having an effect on the projected image with only one coat?

While no definitive tests have been done along this line, in theory, yes, there would be a difference since BW isn't a totally opaque paint; but I doubt the difference would be visible unless a LARGE amount of light was hitting the screen. A number of users have only used a single coat.

If so would a black primer have an opposite effect?

In theory, a darker base coat would provide less reflectance from the top coat, but again, BW isn't all that translucent. The two main reasons for using a white primer as a base coat are to provide a good gripping surface for the BW to stick to and to provide a neutral color base so that any effect the base color might have would not throw off the neutrality of the BW.

What about a higher density of AAA-F in a base coat and a lower density in a topcoat? I can't seem to find much in the realm of layer testing.

While others have experimented with layered mixes, I think they are more or less a solution to a non-existent problem. If a simple single mix can provide good results why make things more difficult? With layering, every layer that goes on will greatly affect the overall result; if even one layer is not correct then the whole screen will suffer. I'm not berating those that have done layered screens, or those wanting to attempt them, but so far the results haven't been good enough to sway me away from simple.

What about wet sanding? How does that effect the performance of a mixture? Would wet sanding increase the chance for hotspotting, or is there a chance it would help to reduce any imperfections that result from rolling?

The problem with sanding a screen is that screens are BIG! It is very hard to get an even sheen over such a large area by sanding. When dealing with metallics in a screen surface the problem is made worse since the metallics tend to show every single imperfection in the screen surface. The greatest problem I remember people having is having a DIFFERENCE in surface texture in a screen (usually a wall). As long as the wall was one texture, even rough, it usually worked; but texture differences pop out when metallics are used.

As for controlling sheen, there are simpler ways than sanding.

The development section has me thinking too much. I can't afford another obsession.

Be mighty careful! This stuff is addicting!!! You have been warned...

[xflapx]

Well if you can neutralize a paint mixture, surely you can neutralize, say a black gloss base and a single topcoat. As long as care is taken in the application of the single coat, it should be a fairly repeatable process, no more prone to error than mixing a solution. The only layering I've read about is silver and it goes in a completely different direction. Anyways just tossing ideas.

I'm only asking because I already know once I have BW up I'm going to have a new hobby. I read the developer's forum top to bottom, but it seems like it's a newer idea and a lot of development and discussion happened in the main forum, or elsewhere. I've read some of it, but obviously it's hard to find the information I'm looking for. Suggestions? Also, I saw somewhere a link to the tool you use to measure fL, but how do you measure the neutrality of a surface? What about grayscale?

Thanks again.

Darin

[mechman]

Have a read here. The elephant in the screen paint room has been this simple experiment. It pretty much proved that very little if any light gets through a layer of paint. And what little does get through, it's doubtful it would make it back the second time around. Granted there was no clear additives involved, but my hunch is that they would have little effect, maybe .5fL.

Using a 100IRE image - one which you wouldn't see much of in many movies - only .77 fL made it through one coat of rolled paint. A more realistic look is that using a 50IRE image, something more commonly seen in normal viewing, only .18fL made it through. With a 50IRE image and a modest amount of clear added (say 25%), I'd guess an improvement of maybe .1fL. And Black Widow has very little clear added to the equation. AAA-f is 25% and maybe half of that or less would be a clear.

Then again, I may be nuts. Cause I did just buy a 4X25 foot sheet of mylar!

I think I'm nuts!

[xflapx]

Makes sense, but I'm not so much thinking about the light returning from the second layer as I am thinking about the black base absorbing the light that does get through. I guess the idea being that it may help with bleeding from one pixel to the next. I'm assuming that the particles of paint don't all reflect the light at the same angle, and that maybe there is a possibility that controlling the scatter of light may effect the detail of the image, especially in brighter scenes. From the screen shots I've seen, grey screens seem to do better with maintaining detail. I figured the darkening of the surface helped to control light scatter which led me to the concept. Obviously this is all speculation from someone who has yet to even build the first screen, but idk, if .18fL are getting through then there is a chance that some could be returning to an adjacent pixel on the viewable surface. Enough to be noticeable? No idea.

[Harpmaker]

It's interesting to note that most techniques I have seen for painting a mirror-like surface (much more so that a simple metallic paint) all call for using a glossy black base coat to get the best results.

As for layering in general, it's harder to control consistency of application than you might think, but by all means try it if the urge strikes. It seems like you have been "bitten by the bug"; it's kinda like being infected with lycanthropy - you might as well just relax, set back and howl at the moon baby cuz there is no cure.

The Developers Forum is an attempt to get the down and dirty process of mix development out of the main forum, but there is so much cross-over that it's sometimes hard to determine where to put a thread. It's more of an attempt to keep the boring stuff out of the main Screens forum for those not interested in how stuff is done.

As for mix translucency, take a look at the last posts (as of now) in the Mirror Experiments thread. In a nutshell, mech painted mirrors with Valspar Ultra Premium Enamel flat white paint and found that even a single coat pretty much killed any reflective qualities the mirror might add to the equation. In fact, a painted mirror was DARKER than a primed surface with the same amount of paint applied. I confirmed his findings. As luck would have it, I was testing an experimental BW mix for making retractable screens that had a large amount of clear medium added to increase the flexibility of the mix. I had some left over from painting a vinyl window shade and sprayed a mirror with it. The result showed that with a translucent enough paint the mirrors reflective properties will make the whole screen brighter (including black areas), but the added cost of using a mirror as a substrate to gain a bit of brightness was probably not worth it except in VERY special situations.

[xflapx]

Hm. I suppose, in regards to the test methods used here, it would be near impossible to quantize an experiment in absorbing excess light. I'm not really interested in increasing the reflectivity of a surface, so the mirror experiment is sort of the opposite direction. I've never had a problem with any display being too dark (unless under-calibrated to be that way), but I've always had issues with displays being too bright, too saturated, too soft, and that seemed to be an issue with my z60. even at 12 ft with the picture zoomed out completely, it was more about doing everything I could to bring out the details in shadows and bright scenes. I just wonder if there is a way to use a layering technique to improve that area. I know once I get BW up I'll be overwhelmed by the increase in PQ, but that will be the zenith from that point forward.

[mechman]

xflapx wrote:

Makes sense, but I'm not so much thinking about the light returning from the second layer as I am thinking about the black base absorbing the light that does get through. I guess the idea being that it may help with bleeding from one pixel to the next.

This is exactly why I've been doing some of these experiments! With mirrors that is. A mirror, in my opinion, as well as many other more knowledgeable folks, would be an expensive and useless substrate to use due to this very thing you mention. The bleeding over from one pixel to the next blurring the image. I think that it also may effect more translucent mixtures as well as they are letting more light pass through to the substrate. And that may be a new reason to forgo the polyurethane additive that others call for elsewhere - besides the fact that it yellows rather quickly.

xflapx wrote:

I'm assuming that the particles of paint don't all reflect the light at the same angle, and that maybe there is a possibility that controlling the scatter of light may effect the detail of the image, especially in brighter scenes. From the screen shots I've seen, grey screens seem to do better with maintaining detail. I figured the darkening of the surface helped to control light scatter which led me to the concept. Obviously this is all speculation from someone who has yet to even build the first screen, but idk, if .18fL are getting through then there is a chance that some could be returning to an adjacent pixel on the viewable surface. Enough to be noticeable? No idea.

My thoughts on this were that the .18fL getting through, had very little chance of getting back through to the adjacent pixels. My uneducated guess is that it would just be absorbed by the base material.

Good stuff Darin! You may end up getting hooked on this stuff. Trust me, you don't want that to happen!

[mechman]

Harpmaker wrote:

The Developers Forum is an attempt to get the down and dirty process of mix development out of the main forum, but there is so much cross-over that it's sometimes hard to determine where to put a thread. It's more of an attempt to keep the boring stuff out of the main Screens forum for those not interested in how stuff is done.

That's my fault. Guilty as charged!

[xflapx]

So why, in the DIY calibration thread, does it seem like Scorpion has such a better reading than BW? I thought it was a dead-on D65 neutral mix, what am i missing?

[custard]

xflapx wrote:

So why, in the DIY calibration thread, does it seem like Scorpion has such a better reading than BW? I thought it was a dead-on D65 neutral mix, what am i missing?

if its the color temps you are referring to, then i would read them with a pinch of salt. the readings on the left are an average of all the IRE grey scale reads. this includes the readings below 30 IRE which is where the colorimeter can be somewhat inaccurate causing the average to be thrown off.

[xflapx]

Fair enough, would it be safe to assume then that the Scorpion mix readings are more accurate because of Scorpion's higher grayscale? Also that a n7 or n6.5 mix would have trouble with readings below 50 or 40 IRE?

[custard]

good question. i understand what you are getting at. if we had 2 screens with reflectance of 50% and 100% then the inaccuracy of the colorimeter at 20 IRE for the 100% screen would be equivalent to the inaccuracy of the 50% screen at 40IRE.
i'll test that theory over the weekend and report back.

the free HCFR program i use allows me to take numerous readings on the lower IRE's and then calculates an average. this helps abit with minimizing the discrepancy. i'm pretty sure that mechs calman program has the same feature.

the spectral relectance readings for BW (and also scorpion) would come through alot closer to neutral. the spectrophotometer having its own light source removes the variable that the projected light may not be completely neutral.

[xflapx]

The ultimate challenge in using that graph will be making sure that negative readings are a result of a poorly performing mix. Maybe with your findings a scale of some sort can be created to eliminate (at least through cross-reference) every other factor.

I love all of the data, it really helps to understand the why and how of mix development.

[mechman]

As custy said Darrin, that number is the average of all the grayscale readings which includes the low end. The low end isn't all that accurate as I don't have the big bucks for high end equipment to get those readings dialed in. If you follow the color gamut and the color tracking graph/chart, you get a better idea of the screens ills/bonuses.

I'm working on a couple others currently, including the original Silver Fire. That one in particular will give you a good idea of what a screen paint that is way off will look like.

[xflapx]

Oh i fully understand, what I was saying is that we could nail it down specifically, and say that for an N8 mix, ignore 0-40 IRE, for a N9 mix, ignore 0-30 IRE, or whatever. Otherwise the graph is somewhat misleading to newcomers. Not that it wouldn't be common knowledge to the testers, but it might help make it more user-friendly for the less informed folk like myself and Harpmaker.

(kidding)

D

[Harpmaker]

xflapx wrote:

Not that it wouldn't be common knowledge to the testers, but it might help make it more user-friendly for the less informed folk like myself and Harpmaker.

(kidding)

D

This is one of the greatest challenges to having an objective, fact-based screen testing forum. Data charts tend to be overwhelming for the average DIY'er. And even though you were kidding a bit above, I have had to ask Mech and Bill many times to explain something to me about the various charts they/we use to document screen performance.

It all depends on how serious one is about their screen. This is one of the reasons we say that many people seeking a DIY screen would do fine with a simple OTS neutral gray paint, but if they are willing to spend a bit more and mix their own screen paint they can gain some performance.

All the data is to prove that we aren't just pulling these numbers out of a hat. We also want to KNOW WHY one mix, or screen, works better than another and we pass that data on as well.

[xflapx]

Sounds good to me! Back to the lab break-time is over.

So is the DVE DVD Disc fine? I don't have a bluray player right now, though I could borrow one to calibrate if the newer version of the VE is that much better... I have to order it and I'm assuming a decent calibration will be necessary to provide acceptable screenshots for the BW beta testing thread.