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Discussion Starter #1
First of all, great wealth of information here. Much appreciated. Im sure the answer to my question is here, but I was hoping I could be led in the right direction. I am a first time projector owner. Purchased an 8500ub a month ago. Been researching a while the best option for the screen. To make things more interesting, I realized rather quickly that I really liked the screen at a larger size than I expected I could throw, and get a quality picture. I have settled on around a 175" image. as far as the room goes: I have all of the walls(except screen wall) painted very dark flat brown, with ceiling painted flat black. Total light control. 21 x 23 room with 9 1/2 foot walls. Started with what the wall was already painted. Picture looked great for what was already there. Then played around a bit.....Kilz2, UPW, found a theater supply store nearby that I got a gallon of Roscos off broadway white white, and a few ideas of my own i just had to try which we just wont go into. Figured I would start basic and work my into some more advanced mixes. That way I would have some good reference points. So far though, the original paint already on my wall has been the best. Roscos being the brightest, and very vibrant, but what was already on the wall is more of a neutral gray color. better blacks yet still nice colors. Porter Provantage interior latex flat. Go figure. Anyway, time to try some bigger and better things. Was hoping to call on your experience in me not wasting my time on a mix that just would for sure not work with the screen size im looking at. I would imagine BW would be way too dark of a shade? Using the calculations at pc, I am getting between 8 and 9 FL at where my projector is located right now. Not sure what mode they are calculating that in though. I just run in THX mode, or theatre mode. Dont want to use the living room, or dynamic mode.

Thanks
 

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Hi Marcus, welcome to the Shack! :wave:

According to the PJC review of your projector it is throwing 638 lumens in Theater mode; for a 175" 16:9 screen that works out to 7 fL, using low-lamp mode drops this 21% to 5.5 fL.. This assumes you are using the PJ at the widest zoom setting, expect another 18% drop in brightness if using the middle zoom or a 36% drop if using the maximum telephoto setting.

Since you are dealing which limited lumens and have a very dark HT setting I would normally suggest a plain white screen, but it seems you have already tried 3 of these and have noticed some loss of color depth and black levels. In that case the answer is a darker neutral gray screen; but not too dark because you simply don't have the lumens for a dark gray screen.

Of the mixes we advocate here, I would recommend Cream&Sugar™. It is a N9 paint (a very light gray), but it has white levels very close to a pure white screen.

All our mixes are designed to have a wide viewing angle since this is what most people want; if you don't need this you could try making Cream&Sugar™ with an eggshell base instead of a flat enamel, but this hasn't been tested and it could hot spot.

BTW, if you want to talk about mica-based mixes here it's OK. Mica done right can work. ;)
 

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Welcome to the Shack Marcus! :wave:

I would really look into making that screen smaller. 8-9fL is not much to work with. And it leaves you no room for when the bulb ages and drops another 2-3fL. But if you're pretty set on that size then you really have one choice and that's C&S. What color was the original wall? The one you say worked the best. Why won't it work if it gives you the best image? Sometimes it may be best to leave well enough alone. And I wouldn't add any polyurethane to the original paint if you decide to repaint. I would think that hot spots would become readily evident on a screen that size with 20-30% polyurethane.

Do you have any of that Rosco's left? I wouldn't mind a sample of that. :bigsmile:

Also, how far back are your seats on a 175" screen?
 

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Another hearty welcome Marcus!

I'll be the one to bear the not so positive news... I know you have your heart set on 175 inches of WOW but it really isn't realistic. Oh I know and understand your projector is making an image that big, but with 8-9fL it's too low. When you hit bulb half life expect your fL to drop to around half of that (thereabouts, not exactly half) which is going to be way too low in anyone's opinion.

You're shooting for 12fL at the screen for total lights out and light controlled viewing. Right now you're nowhere near that. Another thing we need to ask is when you are in your normal seated positions, can you see the entire screen or do you find you have to move your hear around to take in the action? Kind of like watching a tennis match. If so, then the screen is too big.

Now with all that said, it isn't impossible. You're going to need at least a 1.6 gain screen. That's to get you to the bare minimum 12fL. Right now the only certifiable DIY screen with gain that high is benven's CGIV which has a reported gain of 1.8. It's a pretty complex mix though, but still doable if you follow the directions.

We're working on a high gain option but it's not close to being ready for everyday HT use. It definitely has the gain, but isn't neutral and has a bit of grain.

I know you really want this whopper of a screen, but try a couple other sizes too. You might be surprised that the extra brightness makes up for the slightly smaller image. We will try to get you something that suits your needs the best though!
 

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I concur with Bill and Mech about giving serious thought to trying to find a smaller screen size. About a year ago I positioned my PJ so I was getting a measured 6 fL. of illumination on my screen (this is with a 100% white image) and while I could watch movies on it I felt like I should turn up the brightness of the image even with the calibration set properly. Of course, maybe you have better night vision than us and an image that dim works for you, or perhaps you PJ is brighter than PJC says it is. :dontknow:
 

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Ok, and thanks for all of the welcomes. I really appreciate the feedback here. So, first of all, I learned a valuable lesson today. Up til now, I had been painting pieces of sheetrock, and standing them up against the wall to compare different paints. doing it right, priming them first, etc.. But today i decided to just go ahead and paint the entire screen with three coats of the Roscos Off Broadway White White. I learned that there is a big difference in 2 1/2 ' wide 4' high samples, and painting the whole screen. the blacks werent as bad as i thought with Roscos, when not seen side by side with a gray color. Roscos is definitely much much brighter.

Mechman.......I do have about a quart left of the Roscos paint. Let me know what you need, sample wise, and I can certainly get it to ya.

I did try some poly mixed in with the original paint on the wall. Seemed to turn it a bit darker shade, as well as a little bit of hotspotting. Not bad though. Maybe with a bit less poly, i could dial it in with no hotspotting. Went with 3:1 ratio.

Played around mixing some metallic pearl white, and metallic silver, acrylic with the Rosco on a piece of sheetrock over kilz2. Got it very close to the shade of the original wall paint, with a bit more brightness, but not sure how neutral it is. To my eye it looks good. Im sure ill play with it a bit more on a larger sheet of sheetrock.

Oh yeah you asked about seating. Right now seats are about 18' back.
 

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Discussion Starter #7
Another hearty welcome Marcus!

I'll be the one to bear the not so positive news... I know you have your heart set on 175 inches of WOW but it really isn't realistic. Oh I know and understand your projector is making an image that big, but with 8-9fL it's too low. When you hit bulb half life expect your fL to drop to around half of that (thereabouts, not exactly half) which is going to be way too low in anyone's opinion.

You're shooting for 12fL at the screen for total lights out and light controlled viewing. Right now you're nowhere near that. Another thing we need to ask is when you are in your normal seated positions, can you see the entire screen or do you find you have to move your hear around to take in the action? Kind of like watching a tennis match. If so, then the screen is too big.

Now with all that said, it isn't impossible. You're going to need at least a 1.6 gain screen. That's to get you to the bare minimum 12fL. Right now the only certifiable DIY screen with gain that high is benven's CGIV which has a reported gain of 1.8. It's a pretty complex mix though, but still doable if you follow the directions.

We're working on a high gain option but it's not close to being ready for everyday HT use. It definitely has the gain, but isn't neutral and has a bit of grain.

I know you really want this whopper of a screen, but try a couple other sizes too. You might be surprised that the extra brightness makes up for the slightly smaller image. We will try to get you something that suits your needs the best though!
Thanks wbasset,

You know, I really didnt know what to expect with this being my first projector. Just knew it would blow me away regardless. With most of my research I figured upon about a 120" screen. But when I started playing with my new toy, I realized that wow, the picture still looks fantastic at about 175". Larger, and I can start to see more noticable drop offs in brightness. I didnt know the dropoff in bulb output was so drastic. Guess I will take your advice and play with seating closer with a smaller screen, or maybe come up with an easy interchangable masking system to easily make the screen smaller later on into the bulbs life:D.

As far as seating, im about 18', maybe 19' back. Have quizzed everyone on their preference, and so far no one is having any problems taking in the screen size. They prefer it there, And my wife doesnt like to sit too close in theaters. I wouldnt want to sit any closer though at that size.

Thanks for the info on benven's CGIV. Im sure i wont be able to resist trying it, and will let you know the results.
 

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I'd guess you'd have to be at least 18' back with a 175" screen! :yikes:

If you could send me a 8X11" piece of something painted with the Rosco that would be great. Let me know if you can and I'll pm you with my address. :T
 

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Discussion Starter #9
I concur with Bill and Mech about giving serious thought to trying to find a smaller screen size. About a year ago I positioned my PJ so I was getting a measured 6 fL. of illumination on my screen (this is with a 100% white image) and while I could watch movies on it I felt like I should turn up the brightness of the image even with the calibration set properly. Of course, maybe you have better night vision than us and an image that dim works for you, or perhaps you PJ is brighter than PJC says it is. :dontknow:
Maybe its because this is my first projector, but it really doesnt seem too dim to me at that size, especially with the Roscos paint. Obviously I see a difference with a smaller size, but up to 175", the pic seems very good. maybe PJC does have the numbers off a bit idk. I can add some screen shots. The pics wont be quite as accurate as what I am seeing, but maybe you can form an opinion from them. Let me know. Thanks Harpmaker
 

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Discussion Starter #10
I'd guess you'd have to be at least 18' back with a 175" screen! :yikes:

If you could send me a 8X11" piece of something painted with the Rosco that would be great. Let me know if you can and I'll pm you with my address. :T
Definitely. pm me and ill send it off mon, or tue. Any preferences on what u want it on?
 

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Screen photos could be of some help, especially if you tell us what they look like to your eye as well as to the camera. Please use a photo hosting site like photobucket or imageshack and post the links to the photos here. :T
 

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Definitely. pm me and ill send it off mon, or tue. Any preferences on what u want it on?
I pm'd you my address. It needs to be sturdy enough to make it through the postal system. They sell thin 8X11" canvas wrapped hardboard at Michaels I believe. And that should fit in one of those letter envelopes. :T
 

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I pm'd you my address. It needs to be sturdy enough to make it through the postal system. They sell thin 8X11" canvas wrapped hardboard at Michaels I believe. And that should fit in one of those letter envelopes. :T
Sounds good... Theres a Michaels down the street. Got your PM. Will get it out to ya...
 

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Discussion Starter #14
Hey Mech,

Ive already got some CMSM sitting here. Do you want me to mix up some Cream and Sugar using the Rosco White White and include that with the straight Roscos 8x10 sample? I have three pieces of canvas that I can paint. Anything else that comes to mind, let me know.
 

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Screen photos could be of some help, especially if you tell us what they look like to your eye as well as to the camera. Please use a photo hosting site like photobucket or imageshack and post the links to the photos here. :T
Here is an assortment of pics I took. Screen at 175". 16:9. Played with my camera, but it still didnt come out exactly like I was seeing it. For some reason blue colors came out a bit different. Overall the image I was seeing on screen was brighter than the pic for a reference. Some of the areas that almost look like hotspotting in the pics, really werent on screen. Not sure why it came out like that. Anyway, should give you an idea of how bright of an image I am getting at 175" diagonal screen. These were taken with the Roscos Off Broadway white white, not the original color of the wall.

http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus011.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus014.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus016.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus025.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus026.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus029.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus022.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus017.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus018.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus012.jpg
http://i923.photobucket.com/albums/ad80/I_am_legend1970/marcus005.jpg
 

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Those look pretty good to me Marcus! What do you think of them? One of the easiest ways to tell if you're having a problem with hotspots is to take a photo of the screen with a flash from about ten feet away or so. Then invert the image and see how it looks as a negative. There's a thread about it here. I don't see any hot spot issues in your shots at all. I think they look great and I can't wait to get a sample of the Rosco from you. :T
 

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Discussion Starter #18
Those look pretty good to me Marcus! What do you think of them? One of the easiest ways to tell if you're having a problem with hotspots is to take a photo of the screen with a flash from about ten feet away or so. Then invert the image and see how it looks as a negative. There's a thread about it here. I don't see any hot spot issues in your shots at all. I think they look great and I can't wait to get a sample of the Rosco from you. :T
So far im happy with what im seeing. The Roscos definitely brighter than what I was seeing before. We'll see how it holds up when I throw in a couple sci fi space movies. So far the blacks seem fine. Ill put in a couple movies I just recently watched with the prior paint on the wall.

Also In case you missed my previous post, do you want a sample of Cream and Sugar using roscos white white sent as well? Just let me know, as I will have some time tomorrow.
 

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Something to remember Marcus is that the only reason to use a gray screen is to either help the image have black blacks or to fight image contrast lose and poor colors due to ambient light, otherwise a white screen is the way to go.
 

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I did miss the other post Marcus. You can send whatever you would like. :T I told Altern8 via pm that it takes very little time to get readings from any of these samples. It takes more time to make the chart and upload it.
 
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