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post #1 of 13 Old 07-29-07, 09:32 PM Thread Starter
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More questions for the experts...

- When is a screen "flat enough"? I can't think of a good way to make a nice, perfectly flat screen that isn't either expensive or extremely time consuming. Is painting the wall or attaching laminate directly to the wall "good enough" or do you really notice imperfections in the image caused by non-flat walls? My basement walls are drywall and have what I would consider a "typical" amount of deviation from perfectly flat. I have not measured the deviation from flat...not sure how to do so (I guess I could pull a string that's offset from the wall taut and then measure distance between the string and wall?)...but I've looked down a lot of walls in the process of building 2 homes, and the screen wall looks about "normal".
- Is "black velvet" really the best masking material? If one is to go onto a popular auction site and search for "BLACK CRUSHED VELVET YARDAGE", they could find an inexpensive "black velvet", but it looks to me like it might be reflective (though of course I can't be sure). Is this the type of velvet that should be used, or is there some other type?
- Has the "best" flat black paint (I assume closest to RGB 0, 0, 0) been identified for painting the wall near the screen? I'm thinking of painting the wall flat black within 4-6 feet of the screen, but I'm not sure what brand/color is best. I picked up some sample paint chips today at HD and the blackest black that I saw was Glidden "Dark Secret." For what it's worth, it says "00NN 05/000" on the paint chip, which means absolutely nothing to me. Has anyone looked at the neutrality of black paints (would a non-neutral paint surrounding the screen even effect color...or is what the viewer sees based only on the screen itself???).
- Is the color of the room paint (away from the screen) overly important? Seems that the vast majority of folks pick a burgundy...does burgundy have some advantage over other dark colors (browns, blues, greys, etc)? Or is the point simply to have something dark and flat, and the rest is purely aesthetic preference?
- Is there any advantage in covering all of the walls in "velvet curtains"? Or is it just as well with paint?

FWIW, I'm leaning towards a WA laminate screen (paired with Panny AX100U) at this point, likely Designer White (that's the reco from the experts in this forum...whom I completely respect). That being said, I have to admit that I am second-guessing myself a bit based on reading "elsewhere" that grey screens are better than white screens in 97%+ of applications (including rooms with full light control). As I mentioned in my original thread asking about laminate choices, I can control light in the room...but I'd like to have a good picture in moderate ambient light as well (as my wife likes to read, and may want to do so while I'm watching something on the big screen that she's not interested in). I'm worried that the first time that she turns the lights on for reading, my white screen is going to wash out...which will cause me to hang my head in sadness. So confusing...
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post #2 of 13 Old 07-30-07, 12:08 PM
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Re: More questions for the experts...

Quote:
cynical2 wrote:
- When is a screen "flat enough"? I can't think of a good way to make a nice, perfectly flat screen that isn't either expensive or extremely time consuming. Is painting the wall or attaching laminate directly to the wall "good enough" or do you really notice imperfections in the image caused by non-flat walls? My basement walls are drywall and have what I would consider a "typical" amount of deviation from perfectly flat. I have not measured the deviation from flat...not sure how to do so (I guess I could pull a string that's offset from the wall taut and then measure distance between the string and wall?)...but I've looked down a lot of walls in the process of building 2 homes, and the screen wall looks about "normal".

If you haven't read "Working with Rough Walls... A Screen from Nothing', check it out. I know that's not the way you sound like you are going with, but it should ease your mind some knowing if I could turn that wall into a screen, you'll be fine!

- Is "black velvet" really the best masking material? If one is to go onto a popular auction site and search for "BLACK CRUSHED VELVET YARDAGE", they could find an inexpensive "black velvet", but it looks to me like it might be reflective (though of course I can't be sure). Is this the type of velvet that should be used, or is there some other type?

Black Velvet is the premiere choice, but not the only one.
Triple Velvet is one popular choice. Right now I am using Black Suede for my temp test screen and it worked very well. It's around $2.50 a yard too and I am pleased with it. I will get some more information on other choices for you, but in the mean time you can check http://www.hometheatershack.com/forums/26069-post6.html for some of the options.


- Has the "best" flat black paint (I assume closest to RGB 0, 0, 0) been identified for painting the wall near the screen? I'm thinking of painting the wall flat black within 4-6 feet of the screen, but I'm not sure what brand/color is best. I picked up some sample paint chips today at HD and the blackest black that I saw was Glidden "Dark Secret." For what it's worth, it says "00NN 05/000" on the paint chip, which means absolutely nothing to me. Has anyone looked at the neutrality of black paints (would a non-neutral paint surrounding the screen even effect color...or is what the viewer sees based only on the screen itself???).

Unfortunately there is no true black paint available. The closest I have seen is Benjamin Moore's INT RM 12 Black and that comes in at 46 46 46, which is pretty dark. There is a way to deaden it even more and as crazy as this sounds, it really works.... The problem with paint, even flat paint is it reflects light to some degree, even flat black. There is a way to deaden flat black even more (only from a regular can though, this won’t work with spray cans). Add 4 tablespoons of cornstarch per oz. of warm water. Then 4 tablespoons of the cornstarch slurry per 2 oz. of Flat Black paint. Believe it or not this will deaden the flat black down a lot. Here is a link to Tiddler's actual test of this-http://www.hometheatershack.com/foru...66-post69.html

And yes you are right in thinking that it's important to deaden the walls and ceiling around the screen. Here is just an idea of how much light bounce can come off a screen:

Don't mind the slight blur, I wasn't using my tripod for that shot.

Designer White is a very bright and vivid screen. I have a 1700 Lumen projector and when I had my DW screen up it literally lit up the room from the light reflecting off my white walls and ceiling. If you control that scatter light you will have an amazing screen image with the Panny AX100U.


- Is the color of the room paint (away from the screen) overly important? Seems that the vast majority of folks pick a burgundy...does burgundy have some advantage over other dark colors (browns, blues, greys, etc)? Or is the point simply to have something dark and flat, and the rest is purely aesthetic preference?

Most theaters are a Burgundy color, and that's why I think a lot of people go with that color. Plus it is a rich looking color. I am debating on that or a nice slate gray myself. Painting a Home Theater room is almost the opposite of room painting 101- most people go with light colors to liven things up and 'open' the room up with a normal room. What we want for a theater room is a color that doesn't have a lot of sheen (for that scatter reflections) and isn't a color that jumps out and says 'Look at me!' Ideally when the lights go down you shouldn't see the walls, or at least be drawn to them. Now keep in mind that with lights on it could have some affect on your color perception. Just as we use the black border as our black reference, if you were to say paint your room a bright blue or yellow, your eyes would see that as well as the screen even if it's in your peripheral vision. Go with something pleasing yet doesn't draw your attention to it. Plus darker colored walls make the screen look even brighter.

- Is there any advantage in covering all of the walls in "velvet curtains"? Or is it just as well with paint?

You can make a nice 'floating screen' that way, like this one...
http://www.myhometheater.homestead.c...ront_page1.jpg
I think it lends itself nicely to dedicated theater rooms, but it could look out of place in a multifunction family room.
Check eBay, but not the electronics section or under fabrics, look at the Camera's and Photo section under Screens. There are usually a lot of good deals on Draper and Da-Lite road kits and the velvet curtain systems. Some people have picked up some very nice velvet curtains for dirt cheap.


FWIW, I'm leaning towards a WA laminate screen (paired with Panny AX100U) at this point, likely Designer White (that's the reco from the experts in this forum...whom I completely respect). That being said, I have to admit that I am second-guessing myself a bit based on reading "elsewhere" that grey screens are better than white screens in 97%+ of applications (including rooms with full light control). As I mentioned in my original thread asking about laminate choices, I can control light in the room...but I'd like to have a good picture in moderate ambient light as well (as my wife likes to read, and may want to do so while I'm watching something on the big screen that she's not interested in). I'm worried that the first time that she turns the lights on for reading, my white screen is going to wash out...which will cause me to hang my head in sadness. So confusing...

Mech actually has some direct comparisons of Designer White and Fashion Grey with complete light control as well as full lights on. Designer White has a nice gain to it and surprisingly it handles a medium amount of light well... don't expect magic though, but it doesn't totally wash out with some lights on low. Plus with the AX100U you can always kick it up into high mode if the lights are on. DW isn't an ambient screen so just keep in mind that although it is 'watchable' it won't look anywhere near as nice as with controlled lighting.

I was playing with my projector yesterday while I was watching the Chronicle's of Riddick on HD DVD on my 1080p SXRD set. In broad daylight and when I set my gamma settings and brought my contrast and brightness settings up it was actually quite watchable, but still nothing like the SXRD... that thing is a story onto itself though!
If you want to paint and are concerned about the wall (which it sounds like you'll be fine) you can always use liner paper and a skim coat of mud to ensure everything is perfectly flat. Then just apply whatever painted screen method you desire!

"Make everything as simple as possible, but no simpler." - Albert Einstein

"If all else fails, spin the cat."- Grzboken
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post #3 of 13 Old 07-30-07, 07:20 PM Thread Starter
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Re: More questions for the experts...

Quote:
wbassett wrote: View Post
If you want to paint and are concerned about the wall (which it sounds like you'll be fine) you can always use liner paper and a skim coat of mud to ensure everything is perfectly flat. Then just apply whatever painted screen method you desire!

Awesome information, Bill! I can't think you enough for spending the time to help. I will read through it (all of it), digest, and then post back. Thanks again!
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post #4 of 13 Old 07-30-07, 08:01 PM Thread Starter
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Re: More questions for the experts...

Another question:

How is "viewing angle" defined? Eye position to center of screen, or eye position to far edge of screen? Makes a big difference on wide screens, especially if the front row is relatively close to the screen.
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post #5 of 13 Old 07-30-07, 10:23 PM
 
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Re: More questions for the experts...

Quote:
cynical2 wrote: View Post
Another question:

How is "viewing angle" defined? Eye position to center of screen, or eye position to far edge of screen? Makes a big difference on wide screens, especially if the front row is relatively close to the screen.
This is something many don't consider too carefully. Let's assume you are sitting dead center and the projector is only a couple of inches above your head. The light striking the center of the screen is reflected back to you fairly directly. As you look at a spot on the screen further from the center the light has to be reflected back to you at an increasing angle. The screen has to have some retro-reflective ability to do this. A matte surface does have a mix of retro-reflective and angular reflective abilities an is therefore the best at producing a uniform image through a wide viewing angle. Anything we do to boost the gain reduces the viewing angle and therefore introduces issues for some viewing setups.

You have asked a very interesting question that I don't have a good answer for but I do recognize the issues you are raising. This may be especially troublesome with a Pearl Clear Coat if the flakes are for the most part parallel to the screen surface. It would be very angular reflective and have very little retro-reflective ability.
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post #6 of 13 Old 07-31-07, 05:06 AM
 
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Re: More questions for the experts...

Jim . I just paint over plaster , rough as guts with a roller with ultra flat white and it turns out perfect . It is impossible to notice imperfections while the projector is on , give it a go and try it , you wont be disappointed . kind regards Alan.
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post #7 of 13 Old 07-31-07, 06:37 AM Thread Starter
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Re: More questions for the experts...

Quote:
tiddler wrote: View Post
This is something many don't consider too carefully. Let's assume you are sitting dead center and the projector is only a couple of inches above your head. The light striking the center of the screen is reflected back to you fairly directly. As you look at a spot on the screen further from the center the light has to be reflected back to you at an increasing angle. The screen has to have some retro-reflective ability to do this. A matte surface does have a mix of retro-reflective and angular reflective abilities an is therefore the best at producing a uniform image through a wide viewing angle. Anything we do to boost the gain reduces the viewing angle and therefore introduces issues for some viewing setups.

You have asked a very interesting question that I don't have a good answer for but I do recognize the issues you are raising. This may be especially troublesome with a Pearl Clear Coat if the flakes are for the most part parallel to the screen surface. It would be very angular reflective and have very little retro-reflective ability.
Thanks, Todd. Yes, you understand my question (and where I was going) exactly. Though I have to admit that I'm surprised there is no "standard" definition for viewing angle. A lot of people throw around viewing angle numbers for their DIY magic paint mixes...sounds like comparisons of viewing angle could be apples and oranges, depending on who is talking about it?
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post #8 of 13 Old 07-31-07, 03:43 PM
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Re: More questions for the experts...

Man there is alot to know here.
I'm pretty new to projection, i just got my first one a few days ago after about 2 months of research.

I"m looking to get a srceen, but the more I read the more it sound like a DIY may be the best move for me.

I"m leaning towards the laminates discussed at lenghth.

my PJ a sony pearl has 1050 lumen and 15000/1 contrast ratio,

My walls are beige nad celing white, I will have ambient light for the most.

do you think a grey or white screen would work best; as I currently have a pretty decent contrast ratio.

Thanks!

Last edited by adguy; 07-31-07 at 03:50 PM. Reason: sp
post #9 of 13 Old 07-31-07, 04:25 PM
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Re: More questions for the experts...

Hiya adguy and welcome to The Shack!

It may seem a little intimidating at first, but most of what you are seeing is explanations of color balance and data that supports why certain colors were chosen.

Okay we know what projector you have (very nice one by the way ) but we need a little more information. How far back is the projector going to be mounted (I am assuming ceiling mounted?) and what size screen are you looking for?

You say you have ambient light? How much? I'm going to say right now though that you need to start looking at killing that ambient light at the source if it's windows. If it's lighting, go with dimmer switches and lower wattage bulbs.

Here are some quote from the review on Projector Central
Quote:
Projector Central Review wrote:
Overall, when set up to get the best image possible, the VW50 is capable of delivering a dazzling, high contrast picture with extremely deep black levels. Color saturation is outstanding, and color balance is close to ideal. As noted previously, pixelation is non-existent. These performance factors combine to give the picture a rich, natural quality that is easy to enjoy for hours on end.

With the projector's supremely high contrast, one does not need an exceptional amount of lumen output to generate a satisfying picture. That is a good thing, because at video optimized settings most people will opt for, lumen output can drop to lower than average levels. The maximum lumen output we were able to measure on our test unit was 562 ANSI lumens. That was with the projector set to "Dynamic" mode (not ideal color), the lamp on full power, the zoom lens set to its widest angle position, and lens shift set to neutral.
...

The bottom line is that the VW50 has an adequate amount of lumen power to deliver a beautiful high contrast picture in a dark theater. With color balance optimized and the lens in its long throw configuration from a back wall, the user should expect to net about 300 ANSI lumens out of the box. We would not go too large with the screen size, ideally keeping it to no more than about 100" diagonal. If you are viewing nothing but bright, high contrast source material, it will light up a 120" screen quite easily. But with a lot of darker standard definition material in the mix, users with larger screen sizes will find themselves wishing the projector was a bit brighter.
Based on that you should have outstanding black levels and contrast, but they recommend a dark theater room. I would say if you're looking at a laminate screen Designer White is the way to go. It has a gain of 1.24 which will help punch up the image brightness. That will give you around 12fL of light on the screen, which is starting to get on the low end, but should be okay for a light controlled darkened Home Theater setup.

You are really going to want to resolve any ambient light issues and it sounds like a 98" diagonal screen would be optimal for you. If your ambient light problems are from windows, you can get window film from Lowes or Home Depot that will cut down on the incoming light, but it doesn't block out all of it so that your room looks like a cave. You'll probably need to do a little more than just that though, or just go with Blackout Cloth used as curtains. Amazingly that stuff works extremely well for its intended use!

If you decide for some reason you need a gray screen, which I really don't think you do based on the black levels and CR, don't go any darker than an N9 in shade. You already are a tad low on lumens and a darker shade will suck them up real fast and give you a dim, muddy looking image. But if that's what you decide on, make sure it is as neutral of a gray as possible.

Quote:
Projector Central Review wrote:
The VW50 needed a minimum of color balancing to produce a pleasing image that read near 6500K across the grayscale. With a bit of fine tuning, we neutralized our test unit's slight greenish-yellow cast, and the result was balanced, natural color with excellent saturation.
If the screen pushes green or blue like some gray screens can, it will only accentuate the projectors greenish-yellow cast and could make it harder to calibrate and pull it in to D65 calibration specs.

So my advice is figure out your mounting distance and how you are going to mount it, (this is a larger and heavier unit) what size screen you want- 98-100 sounds like the max you'll want though, and take care of your ambient light problem.

"Make everything as simple as possible, but no simpler." - Albert Einstein

"If all else fails, spin the cat."- Grzboken
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post #10 of 13 Old 07-31-07, 04:36 PM
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Re: More questions for the experts...

wow!!

thanKS for the detailed and insightful response.
The PJ is mounted on the ceiling currently using the textured wall as a screen. It actually looks OK. but i know there is so much more untapped detail to uncover. It is mounted about 13 ft from lens to wall.

I am thinking a 100" or 98" would do fine 16/9 screen.

the light can be controlled I said ambient because this is not a dedicated theater room, I will have my PC hooked up as third monitor and often use it with the lights on and or the window light. I have dimmers so at night when i wantot watch a movie i can dim the ceiling lights so this i figured was ambient as well.

what you said about the screen color makes sense to me, I 've been debating on the white vs grey. but with the built in level of contrast for the PJ I think the white is the better idea.

I"m going to try and get it built this weekend! I'll post soem pics as soon as I can.

thansk for the help Bill
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