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DIY Screen for Lumen Challenged LED Projector

post #1 of 19
Thread Starter 
I'm currently having a Media Room built with a house conveniently attached. biggrin.gif I picked up an LG PA70G at Fry's since I believe I wouldn't enjoy the projector experience as much with "bulb anxiety," so the LED jobber will have to fit the bill for a few years before it seems LEDs move more into the dedicated HT market.

Here's a pic of the media room:

mediaroom.jpg

The actual room will be a bit shorter on the bottom end (the screen side) since we added another bathroom upstairs which uses about 2-3' of the front of the media room for a closet (I know... horrible... but the CEO/CFO provided some gentle guidance on this point... tongue.gif). It's still a reasonable size for my purposes, so it'll be plenty long enough for 2 rows of seating eventually, and maybe a riser in the far future. I figure my primary seating distance will be somewhere in the 10-12' range depending on the size screen.

Anyway, here's some details. The LG is rated at 700 lumens, so I imagine in its brightest mode it's probably in the mid 500 lumen range with a watchable calibration, but the fan is loud in this setting, so I'll likely use it in its medium brightness mode. I estimate medium brightness probably knocks 10-15% off - so maybe 450-500 lumens in normal output, with very low fan noise, so this is as dim as it's going. My viewing will be probably 20-30% movies, 40-50% TV, 10-20% gaming. It's only a 720P unit as well, but should work at my seating distance and content.

The room will have complete light control, but occasionally I'll want to have some very low ambient light on. I figure I'll optimize the screen size and composition for the medium brightness setting, and then deal with the higher noise and minor image washout by using max brightness with any ambient light exposure.

My screen size goal is 120", but I'm not sure the projector has the brightness to run a screen that large. Going significantly below 120" starts to make the readily available 4'x8' material start to look more attractive, but I don't really know if I'll be happy with <100" in the long run, and I think the projector has a little more oomph than that. I'm thinking I'm after a little more gain than I see on a lot of DIY screens here if I want to push the size.



So do all signs point towards a trimmed 5'x10' 6mm thick piece of Sintra?


What about the paint? MM Low Lumen, or maybe S-I-L-V-E-R?
post #2 of 19
S-I-L-V-E-R would be optimal....if really effective light control is designed into the room. That does not mean that it has to be "total" by any stretch, just intelligently planned.
Using the proper type Bulbs, as well as directed Can Shields (Eyeballs or Wall-Wash) will make all the difference, and allow you far more flexibility as to what type of Screen surface you can go with. Let's work this out carefully. You can expect excellent results...because if S-I-L-V-E-R can do the job desired on a 220" screen with a 700 lumen JVC RS-2, it will certainly get the job done on your ittsy bittsy 120"er. biggrin.gif

Here are two shots that represent S-I-L-V-E-R's potential in your case:

These first shots are ones that show high ambient light within the overall room, but more importantly the effect "Directed" Spot Lighting has on the corners of the screen. Note how well resolved the center of the image remains:

Image113aStagew-TruckinAmbient.jpg

Image201-BlackButtshot.jpg

........but when those Spots at each corner are dimmed to less than 15%.....?

Image218-MeganMidrift2.jpg

The next shot shows the effect that the spots have on the image at 25%.

Image229-Anicepuppydog.jpg



Noticeable...but as i stated above, plan your lighting so that the umbra (cone) of light never washes the screen and your results will be spectacular


So........? Waddaya thin?
post #3 of 19
Thread Starter 
I believe the two lights in the media room are can lights, so likely very little light will hit the screen if they're on. But I honestly don't mind a good 80% of my viewing to be with the lights off. IMO, it kills the "big screen" experience when the lights are on and you can easily make out your surroundings.

So S-I-L-V-E-R does sound like what I should shoot for. Roughly what sort of gain and formula should I shoot for? It doesn't seem quite as well documented (or I'm searching the wrong terms) as the MM mixes.



For general light control, or "reflected light control" as I think you are talking about, the carpet will be light colored, but I plan to paint the walls and ceiling a dark color in eggshell. I'm thinking something like a dark grey/green would be moderately appealing with the lights on, but offer fairly good light control. I could probably toss a rug in front of the screen to help control reflected light off the carpet if you think that'd be a big problem - maybe something really nerdy along Star Wars/Star Trek lines. It's MY room afterall (I think the CEO will have decorating decisions on the rest).

I've seen those screenshots before, and they are mighty impressive.
post #4 of 19
Thread Starter 
I did a quick audition on a (I believe) 1.3 gain Screen Innovations 120" screen last night, and with the PA70G at around ~115" or so, it was perfectly watchable in the medium brightness mode with some soffit lighting dimmed about halfway. The permanently installed JVC HD-1 in the room with a new bulb on normal lamp mode was conversely fairly washed out at that light level. Of course, the JVC trumps the little LED PJ on resolution and black levels (really trumps it on black levels I should say!), but the PA70G's brightness really surprised me. I'd say it's medium brightness mode might even be a hair brighter than the HD-1's high lamp mode, and the PA70G in high brightness was definitely the brightest of the two. In fact, I could watch the PA70G with 4 60W can lights on full blast and it was slightly washed out, but not horribly so... and I never see myself watching stuff with that much ambient light.

So I can sum it up that I was somewhat shocked with the PA70G's overall brightness. It appears to be punching well above its weight, so maybe there is truth in LED PJs appearing 25% brighter for a given lumen output due to how saturated the colors are (I did a quick calibration, but colors were still a little oversaturated, especially green, but it wasn't like the out of the box torch mode).



So with that in mind, is S-I-L-V-E-R still the way to go? I'm feeling much more comfortable with shooting for around 120", I guess now I need to decide what gain to shoot for. I do like a punchy image. Also, is the gain on S-I-L-V-E-R very retro, as in will it work fine with the projector being a few inches above the top of the screen (I believe that's the very small offset built into the LG)?


I do have a small compressor and an HVLP gun, so that's not a problem.


Thanks for the responses again!
post #5 of 19
Thread Starter 
Some more reading completed. What about RS-MM Retro v2.1? After comparing my little LED guy to a JVC HD-1 on a traditional 1.1 to 1.3 gain screen, I am getting more comfortable with how much light it puts out. The black levels are not stellar on this thing, so I think the darker mix of RS-MM Retro might be a benefit.

Or should I maybe look at SilverFire?


S-I-L-V-E-R seems like an older mix, and it seems hard to spray it well. I do have some experience spraying paint (on cars mainly, but also interior latex thinned slightly), but obviously never a screen.


I think anything in the 1.4-1.5 gain is likely to look pretty good with this little guy.
post #6 of 19
RS-MM Retro would certainly work to kick up Contrast more than a few notches....but it's not going to provide the levels of gain you mentioned. It's more specifically designed to enhance the image due to the inherent properties of a Silver metallic based mix.

It may seem old...even passe, but S-I-L-V-E-R's performance index is the highest I have ever experienced for such a simple concoction. Yes...it's make-up requires careful application done in several coatings, but there is nothing overly difficult about it. Just consistent repetition of correct spraying technique. And BTW, the change up to suggesting "Duster Coats" with all the Silver Fire versions is directly related to the use of same with S-I-L-V-E-R. Having Noobs take the same care taken when spraying S-I-L-V-E-R helped prevent the cases of people experiencing Runs from the thinned SF paints.

S-I-L-V-E-R is the only mix that would reach up into those higher gain figures. And it does so without undue loss of viewing cone. rest assured, it will improve your Blacks. Not like a true darker Gray....but enough to make you be pleasantly surprised....that's for certain.
SF 2.5 2.0 would top out at 1.2 - 1.3 gain at most
post #7 of 19
Thread Starter 
Gotcha, I've searched and not found a recent S-I-L-V-E-R mix formula with readily available components. Any help with that?

Looks like it's just 2 parts, using the "hot" silver mica at the time (Liquitex Basics Silver?) at about 5%. What's the rough gain amount for that mix percentage? Or should I go up closer to the 10% you used for the above screen shots (found that thread in my searches)?





As for hanging the Sintra - I've thought about stepping down from a 122" image by using ~1" on each side to screw it into the wall (probably go with one every 32" around the perimeter), then hang the velvet masking border over the screws. Alternatively, it seems like a frame around the Sintra with a french cleat is popular. I suppose I could build it as all one unit, but I don't exactly see myself moving this screen around too often once it's hung.
post #8 of 19
Thread Starter 
BTW - came across a few people claming that RS-MM LL v2.1 is about 1.4-1.5 gain? If true that seems sufficient and should help out the contrast, or is S-I-L-V-E-R still the hot ticket for my situation?
post #9 of 19
Quote:
Originally Posted by RPS13 View Post

Gotcha, I've searched and not found a recent S-I-L-V-E-R mix formula with readily available components. Any help with that?
Looks like it's just 2 parts, using the "hot" silver mica at the time (Liquitex Basics Silver?) at about 5%. What's the rough gain amount for that mix percentage? Or should I go up closer to the 10% you used for the above screen shots (found that thread in my searches)?
As for hanging the Sintra - I've thought about stepping down from a 122" image by using ~1" on each side to screw it into the wall (probably go with one every 32" around the perimeter), then hang the velvet masking border over the screws. Alternatively, it seems like a frame around the Sintra with a french cleat is popular. I suppose I could build it as all one unit, but I don't exactly see myself moving this screen around too often once it's hung.

A 1' boarder is pretty skimpy, but if you select 2.25" MDF Base for trim, it can work out.

The 10% ratio I used above was for two reasons.

1. I wanted maximum gain because the Screen was Soooooooooo big and the PJ was only 700 lumens.
2. Seating was to start a full 15' away so i had no worries about "Speck-ularity". Turns out....there wasn't any anyway. rolleyes.gif

You could probably crowd 10% with the Liquitex because it's a finer grained Mica mix.
Quote:
Originally Posted by RPS13 View Post

BTW - came across a few people claming that RS-MM LL v2.1 is about 1.4-1.5 gain? If true that seems sufficient and should help out the contrast, or is S-I-L-V-E-R still the hot ticket for my situation?

RS-MaxxMudd LL would do fine at 118" diagonal and the resulting 18+ fls
post #10 of 19
Thread Starter 
I probably didn't explain it well. I was thinking of screws 1" inside from the perimeter, then a velvet trim border being built that just covers the screw heads and is the usual 3-4" wide all around. I'd probably be hanging the border I imagine.



So roughly what sort of gain would an 8% silver S-I-L-V-E-R mix provide? I'm guessing the RS-MM LL would give slightly better contrast given that it's intended purpose is to help improve apparent contrast.
post #11 of 19
Quote:
Originally Posted by RPS13 View Post

I probably didn't explain it well. I was thinking of screws 1" inside from the perimeter, then a velvet trim border being built that just covers the screw heads and is the usual 3-4" wide all around. I'd probably be hanging the border I imagine.

No...I getcha. I hang Sintra in that manner all the time. but I usually have about 2" space between the edge and the Screen area, because when you miter the corners...and then place the trim on top the outside edge and nail it into place, the broader footprint on the Sintra helps keep the Trim from rocking backwards and keeps the Corners flush and even. Even with using 2.25' wide Trim, there would be at minimum 1.25" of non-backed trim hanging over, and it's at the Corners that having support is so critical.

Oh my....what to do???? Simple really. One inch doesn't allow much leeway....but by taking small 4" x 2" strips cut from the piece of 13" x 60" of trimmed Sintra (....be sure to have them save it and give it to you to take with you...)and placing them at the Corners and along the outside edges, you'll provide a spaced support "ledge" for the Trim to lie against. I advise against trying to constrict a free-hanging Trim Frame. It would require effective support and bracing at the Corners, and would have to be "Hung" extremely precisely. That's a lot of hassle. (...been there, tried that...)

First off...you want to use 1.25' "Truss Head Screws" (Sharp Point...not Self Tapping) to hang the sintra to the wall because they have extremely Flat, broad heads. Secondly you want more of them than just one every 32'....more like one every 12' to 15" minimum (trust me on this) even if eventually your adding 1.5" bright Finish Nails through the Trim and underlying Sintra tabs and the 1" boarder area. I've attached a simple diagram below. It was actually based on a Spandex sheet stretched on a Frame and the adding of 1 x 4 x 2" blocks to provide nailers / support for a overlying Frame....but the principle is the same. Just consider the "Frame" as being the Sintra. :

Framew-BlockBackingforTrim.jpg


Quote:
So roughly what sort of gain would an 8% silver S-I-L-V-E-R mix provide? I'm guessing the RS-MM LL would give slightly better contrast given that it's intended purpose is to help improve apparent contrast.

Close in on 2.0 minimum gain. (...it's so effective, even those who know better often state it appears to be 3.0 gain or higher...) BTW, in the dark, S-I-L-V-E-R does provide greatly increased perceived Contrast as well as work to preserve / improve the dynamics of Colors & Whites. But it's lighter shade along with it's gain makes it much more acceptable to washing out under higher levels of ambient light, and it does poorly if subjected to "ANY" directed light. To wit, it's best as serving as a Dedicated Theater Screen.

RS-MaxxMudd was originally intended to replace the MMudd-SE (Silver Edition) formula that used Behr Deep base instead of Polyurethane. It was back then designed to allow a small amount od Silver within a Translucent Mix to provide both a nice boost in Contrast while maintaining a gain higher than 1.0. In fact, the degree of ambient light resistance it provided was a bit surprising. It's not a capable at doing such as Silver Fire, but for a light "Silvery white" surface....it does a pretty effective job as long as any outside lighting influences are in the least kept under reasonable control.

The "LL" version has even higher gain, and is an even lighter "Silvery white' so one can expect it's level of sheer ambient light resistance to drop a bit. But as stated...it still does much better than any non-metallic surface of the same color and hue.

Under given ideal circumstances...S-I-L-V-E-R will outperform RS-MM-LL in the contrast boosting dept. Every time. No exceptions. Introduce ambient light and as such light intensity rises, the advantage lessens and then recedes below RS-MM-LL. Were it not for the need to apply S-I-L-V-E-R in so many multiple, ultra thin Duster coats, you'd see me advocate it for dedicated theaters far more often than i do.

Instead, I find it's best suggested as the "Go To" application where Screen size is "BIG"....lumen availability is lower than recommended for such a size, and ambient lighting is held in check...if not completely in control.
post #12 of 19
Thread Starter 
Gotcha. S-I-L-V-E-R it is!

I'm going to think some more on the Sintra/edging hanging. There's got to be a better way to do it than what I'm envisioning...




Thanks for all the help! I'll be sure to update this thread as the house actually gets built and then start gathering my materials.




BTW - what do you recommend for a wall/ceiling color for a dedicated theater? I think I might want something other than flat black, but obviously something dark.
post #13 of 19
Quote:
Originally Posted by RPS13 View Post

Gotcha. S-I-L-V-E-R it is!
I'm going to think some more on the Sintra/edging hanging. There's got to be a better way to do it than what I'm envisioning...

Of course there is! I just showed you above. Nothing is easier than screwing the Sintra up onto the wall, then overlaying Trim over the Screws. That's how I roll with it 99% of the time, and time and ease of installation is paramount to me.
Quote:
Thanks for all the help! I'll be sure to update this thread as the house actually gets built and then start gathering my materials.
BTW - what do you recommend for a wall/ceiling color for a dedicated theater? I think I might want something other than flat black, but obviously something dark.

Oh Goodie! I get to be your decorator now! I actually love that because when it comes to choosing Wall / Ceiling colors, the right input can afford the best possible results.

Beah...Black is pug-ugly...and in fact not really all that effective. A Flat Black...besides looking "dusty'" and dullish will reflect a Blue-ish cast when bright digitally projected light hits it. People just tend to think "Black" when they think "Dark". And Black seldom garners much of a WAF. (Wife Acceptance Factor) Let the ladies toy around with colors that actually look good when the lights go up and everyone is happier.

Rules to go by:

Color Scheme should be reversed in a Theater, with the Ceiling being Darker than the Walls, and Door-Base-Crown trim matching the Ceiling.
Walls & Ceiling paint should be in "Flat"
Trim should be in Satin Interior Enamel, and sprayed on to mitigate any overt reflective tendency. If rolled on, use a "For Semi-Smooth Surfaces" Roller cover.
Colors should be of the "Cool" variety.... Darker Grays, Dark Blues or Greens, or combinations of each mixed to create Gray/Blue- Blue/Green hues. ***
Browns and Reds should be avoided as they reflect a yellowish cast. Ultra dark, Flat Reds can work for walls though if the Walls don't crowd the sides of the Screen. Any Flat Brown dark enough to work well is essentially gonna look almost Black anyway.

*** My personal favorite Combo? Dark Blueish Gray Walls and a very Dark Gray Ceiling

One other thing. The Wall the Screen is on cannot reflect any of the Screen's output, nor does any reflection of ambient light or directed light off the Screen wall have any effect on the screen. Many people go to great lengths to get a virtually blacked out Screen Wall. The truth being that for the wall to play any real part in things, it's level of "darkness" need only to match that of the surrounding dark wall color. The Black velvet Trim is the only real needed reference, and even then it only makes a difference when there is enough room lighting to show the difference between it and the Screen wall's color.

Lastly...the Floor. Next to the Ceiling, it is the singular most culpable culprit in receiving reflected light from the Screen and lighting up the room. Choose your Floor covering wisely.
post #14 of 19
Thread Starter 
Maybe I'm overthinking the attachment method... but I am a mechanical engineer, so the overthinking part is pretty much hardwired into me at this point. smile.gif


The carpet is going to be fairly light, so I am thinking of a larger throw rug to put down in the front of the theater to cut down on reflected light, as that can definitely be distracting and kill what meager black levels I've got to work with.

I'll likely just paint the whole room one color, but I was thinking of a really dark green with possibly black (or maybe a really dark grey/green) trim and doors (although the doors are not really a problem for reflections as you can see in the above floor plan). I'll look into the dark blueish hues as well.


I'll likely build a riser in the back in the future with the goal of raising a back row of probably 2 seats (maybe 3) and then knocking down some noise going to the lower floor. That part is slightly hanging over a part of our master bedroom, so a good sized riser should really cut down on transmitted noise.



Thanks again for the suggestions, I'll go do some more homework.
post #15 of 19
Quote:
Originally Posted by RPS13 View Post

Maybe I'm overthinking the attachment method... but I am a mechanical engineer, so the overthinking part is pretty much hardwired into me at this point. smile.gif

Better to over think than overlook. tongue.gif
post #16 of 19
Thread Starter 
Bumping this thread back up since we FINALLY closed on the house and moved in (or should I say cohabitating with dozens of boxes at this point...).

I did take the time to put the PA70G up in the media room and get an idea of the size I'd like, and I actually ended up liking a screen in the 110-112" range. I've got two Acoustech HT-75 floorstanding speakers, so that kills some of the 10'1" wide wall I've got to work with, and I found the screen reflections on the walls getting much worse as I started going up on size beyond about 112" diagonal. I will say the brightness of the PA70G is actually not bad on just a builder-biege textured wall. The settings need to be boosted a bit since it's probably in the 0.8-0.9 gain range with lots of light scatter, but it's definitely watchable - so it can only get better from here!

So thoughts on materials?

Sintra sounds nice, but it seems spandex is garnering more of a following for a general DIY type budget screen.

I'd like brightness, but the blacks of the PA70G aren't exactly stellar to begin with (15,000:1 contrast must be measured with cranking all settings to max to take the white measurement, then killing all settings to take the black measurement... hah). So does that call for Silver over White spandex, or White over Silver?


Painting drywall isn't a go since my instructions on where to place the speaker wire box wasn't exactly followed , so one box is just inside the screen area by about 4-5" on one side. So definitely need something to hang. Doesn't need to be particularly lightweight, but 1x4's and a french cleat or two sounds like the easiest way to go. I would also like WIDE border trim, since this is actually a 16:10 PJ that will be used as a 16:9 setup, so the top and bottom black bars are a hair over 3". I suppose 3.5" would work, but I'd hate to have some light spill.


So painted sintra (or other substrate) or spandex?
post #17 of 19
ONLY consider Painted Sintra, using either S-I-L-V-E-R as originally suggested, or the less effort (...but somewhat more expensive...) RS-MaxxMudd LL.

At this conjecture you cannot afford to sacrifice any more Lumen. Spandex...even the White, will gobble up too high an additional percentage.

S-I-L-V-E-R will optimize both your available Lumens and enhance your contrast on screen. RS-MaxxMudd LL does the same but adds the ability to have a better image with with some ambient light present, and doesn't require as many ultra light Duster coats.
post #18 of 19
Thread Starter 
So spandex is <1.0 gain due to the open structure of the fabric, even with 2 layers? Interesting, I don't think I've seen that mentioned in the dozen+ threads I read on it.


Anybody have any good sources for 5x10 Sintra/Expanded PVC Foam in Houston? I really wish there was a cheaper solution for a substrate for >98" screens. The Sintra gets kinda pricey in 5x10' at most places I've been able to find.
post #19 of 19
Quote:
Originally Posted by RPS13 View Post



Anybody have any good sources for 5x10 Sintra/Expanded PVC Foam in Houston? I really wish there was a cheaper solution for a substrate for >98" screens. The Sintra gets kinda pricey in 5x10' at most places I've been able to find.

The realization of the need to have an adequately sized AND smooth surface that will readily acceot paint requires one to spend at least the minimal amount to acheive such. Add to that the absolute need for a higher gain paint solution, that itself requires a smooth surface and there is really nothing else to do but do what needs to be done.

One can use 2- 10' x 4' 1/2" sectional-ized Drywall sheets, each cut to 100" x 31", hung so each Tapered edge is at the center, and then finished and primed for far under the "cost" of a cut to order 54" x 96" Sintra surface. But there is the logistics and effort involved in getting that Drywall up to the same level of smoothness ro be considered.

Or...getter' dun using a 5' x 10' Sintra cut to 58" x 102" and do it all with assured results and no muss or fuss for approx.$130.00

Here is your local source.

Laird Plastics of Houston
555 Garden Oaks Blvd
Houston, TX 77018
Sale Reference: Ed
Phone:800-445-5217

Lastly, the same location above has the Sintra 5' x 10' ers in 3 mm thickness. For substantially less. But using such requires that it be applied to the wall much like a sheet of laminate, using thin, trowel smoothed adhesive and effective rolling out so that there are no lumps or ridges from either adhesive or any underlying texture from the wall's surface. You don't have to worry about "finishing" the surface of the Sintra...just hanging correctly.

BTW, the extra 2" around the edges my measurements allow for is to facilitate a space to use screws to hang the Sintra or Dywall directly with Screws, and then cover the screws with 2.5" to 3.25" Velvet Wrapped Trim
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