Home Theater Forum and Systems banner

1 - 20 of 21 Posts

·
Registered
Joined
·
290 Posts
Discussion Starter #1
I'm looking to build a screen in the next week or two. I'd planned to purchase blackout material from Carl's place due to the cost vs performance. I had done research on the colors and gains, and how that works to your room with ambient lighting and wall colors. My room is dark brown on the walls and white on the ceiling/slant walls. It also has controlled lighting. there is a window right where the screen would go, but that will be blacked out as well (any suggestions while I'm at it?).

I plan to use the Epson 8350. I am looking at using in the neighborhood of 100" diagona screen.

The room dimensions are 15ft wide x 26ft deep. The wall the screen will be mounted to is about 106" wide and 8ft high. The PJ mount in the ceiling is about 15ft off the front wall, which is also roughly where I plan to be seated.

So, that led me to think the blackout cloth with 1.0 gain was the best route for me. However, I'm still a bit unsure about this given the fact that the ceiling and slant walls are white. I've attached a picture below. If you guys can tell me if the blackout will still be a viable option or not, I'd appreciate it. Is there a better recommendation here?

Thanks for any input,
Erin
 

·
Banned
Joined
·
14,914 Posts
From what I understand, blackout cloth's gain isn't generally considered 1.0. It's slightly less than that.

That being said, I would just go ahead and use the BOC and see if it works for you. If it doesn't, you can always paint it if need be.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #4 (Edited)
I posted this same question on avs and was met with a pretty resounding "do not use BOC". The reason given was that the white ceiling and slant walls would be a nightmare in regards to reflections. So, I started looking at gray screen options.

So far, this is the best I could come up with:
http://www.buildyourownprojectionscreen.com/front-projection-high-contrast-grey-fiberglass-material

They also have a metallic PVC version but it's about $100 more for the material.

I'm pretty much stuck. If the room were all dark, I'd think white screen material would suffice. But since I have zero experience with this stuff, I'm having to assume that gray is the direction I need to go.

Specifics have been nailed down to: Epson 8350, 110" diagonal, 12-14ft viewing distance, and approximate PJ mount 15ft from screen. This can be changed some... I could possibly eek it to about 14' but that's all the slack I have in the HDMI cable. I'd like to stay under a $200 budget for this screen, figuring about $30-40 in raw materials, leaving about $160-170 tops for screen material.

Any input here based on my specifics would be GREATLY appreciated. I'm just ready to get this ball rolling and move on from this screen research that has literally consumed my last two days. I'm getting a headache from all this back and forth and feel like I'm no closer to a purchase decision now than I was when I started the research. :(
 

·
Registered
Joined
·
290 Posts
Discussion Starter #5 (Edited)
Did a bit more reading. As I understand it, unless I paint, my only real option is a gray screen with a low'ish gain value, around 0.8 or so. This would mean more light is being absorbed by the screen, so less is being thrown "back out there" in to the room, helping with reflections off the ceiling, but that also means the PJ will need to burn brighter to increase the overall brightness on the screen itself.

Since I had no idea what a 'typical' brightness was for most HT, I dug around and found that people shoot for the 12-15fL mark, depending on personal choice. Then I needed to account for potential burn in, so I put my mark at 14-17fL.

Here are my "knowns":
Epson 8350
Screen Size = 110"
Fixed PJ Location 14.5-15 ft from screen
Screen Gain 0.8

Pulling up the PJC calculator, and using the default Zoom/PJ values (1.55x @ ~ 14.75ft) changing to 0.8 gain, I get 13 fL. That's not quite enough.
So, I then zoom in to 1.73x and get an effective throw of 13ft, which results in 16fL. Looks like I'm OK to use a gray screen with lower gain, and keep the life of the bulbs pretty reasonable at the PJ mount location.

Does that seem right to you guys? If so, I'm going to go through with ordering the gray screen material linked above because I can't find any better alternatives.


Here's a couple photos to supplement the above. In the first picture, you can see the HDMI cord hanging fromt he ceiling. That drop location is about 15.5ft from the front wall. With enough slack to get me a PJ mounted about 14.5 ft from the front wall.

The blue tape is taped off to give me the approximate size and location of the 110" screen at 14 ft seated distance (pictured from the seated distance in the 2nd photo).




 

·
Premium Member
Joined
·
519 Posts
Just bare in mind that announced gain for the screens is usually incorrect especially on gray screens. Many of them say that are 0.8 when normally are around 0.6-0.7. If i were you, i would set up the distance so i could get a reading of 18 FL to be in the safe side. Furthermore, you have to consider the intensity loss of the lamp during time which could be another 20% or so.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #8
That's good info. I did account for some loss of life, which was mentioned in my post. I tacked in another 2 fL for this, which is what put me in the 14-17 range, based off reading that the average people tend to use is 12-15 fL.

But, I didn't realize that all gains are not created equal. No surprise, just wasn't aware. Lol.

With the zoom, I still have some leeway, so I think I'm OK.

Thanks again for the input.
 

·
Premium Member
Joined
·
519 Posts
That's good info. I did account for some loss of life, which was mentioned in my post. I tacked in another 2 fL for this, which is what put me in the 14-17 range, based off reading that the average people tend to use is 12-15 fL.

But, I didn't realize that all gains are not created equal. No surprise, just wasn't aware. Lol.

With the zoom, I still have some leeway, so I think I'm OK.

Thanks again for the input.
Mech gave you a great tip, but the greatest and most safe thing to do is to get a lightmeter and take the readings yourself (it costs around 30-40$).

It's one of the most useful devices that come very handy when you need to consider illuminance.

There are so many parameters in considering the light from your projector that no calculator online could tell you better than a lightmeter which is used by you.
 

·
Moderator Emeritus
Joined
·
3,772 Posts
Hi Erin. Got your PM and am jumping in here with my $.02. Family health issues have risen to a roar lately and that affects my forum participation.

While we haven't measured the gain of BOC, the samples I have gotten myself, and had sent to me, have had no detectable gloss or sheen to them whatsoever so I would assume that their gain would be very close to a Lambertian surface the same color (one that reflects light equally in all directions). For the N9 that most BOC has proven to be that would equate to a gain of ~0.75. While I can't be certain, I believe the screen fabric you linked to is darker than that (which is a good thing for your situation) while having a gain of ~0.80. This means it has a small amount of gloss (thus increasing the on-axis gain), but yet is far from hot spotting.

When it comes to screen brightness things get VERY subjective. I know some folks that can't stand to watch a screen that isn't reflecting at least 16 fL of light, yet both Mech and myself have no problem watching a 12 fL or ever 10 fL screen. :huh:

Sadly, I must suggest that you take any gain figures from AVS DIY Screens with a VERY large grain of salt since they are determined there, at best, by the naked eye - which just doesn't work for the same reason most film cameras came with light meters. - the human eye is horrible at determining how bright something really is; but it is amazing at compensating for lighting conditions so we can still detect images. Besides the iris opening and closing like a camera lens shutter, there are chemical changes that occur in the eye when the light really gets dim to boost our ability to detect images.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #12 (Edited)
Thanks, guys, for your feedback.

Don, thanks for replying. I'm sorry to hear about your family situation. Hope all is well soon.


After looking at these DIY paint mixes, I've decided to punt painting altogether. Not even time and I don't have a good HVLP (I have a cheap one and my little junky compressor doesn't like the load). I'm pretty much gunning for this screen material, unless others have concerns:
http://www.buildyourownprojectionscreen.com/front-projection-high-contrast-grey-fiberglass-material

That really just leaves the question of lumens, and the feedback here coupled with my research points at its subjectivity. With that said, I think leaving myself a range of 14-17fL I mentioned earlier would probably suffice in providing both output and degradation of brightness over time. But, I'll flex that window up to 18fL just in case.

So, that takes me back to the calculations again. This time, using MechMan's link. I used a gain of 0.80.

In both cases, I had to adjust the throw to around 13ft, give or take, with a zoom ~ 1.92x. I stopped here because I felt like I was running too close to the max zoom (2.10x) if I went any further. From that, my best setting would get me about 14.7fL at full life; 11fL at 25% life.

The picture below is what I came up with.

110" screen, 0.8 gain, 1.92x (out of 2.10x max) zoom = 14.7 fL at birth.






So, it seems I either run the zoom up higher, or go with a smaller screen. So, I tried to see what a smaller screen nets me. Using the exact same settings as above, BUT using a 100" screen instead I get: 17.5fL (13fL @ 25% life). The picture below illustrates:

100" screen, 0.8 gain, 1.92x (out of 2.10x max) zoom = 17.1 fL at birth.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #13 (Edited)
Based off the above, I'm still not sure which is the obvious choice. It certainly appears the 100" screen is the obvious choice, as it provides brighter output which is needed for the gray/0.8 screen. Still, I'd like to go with the 110" screen, but not just for the sake of doing so. In the painter's tape pictures I posted earlier, it looks to me that even with 110" it may be on the smaller side. I'm worried that a 100" screen may be too small.


If you guys see anything crazy here, please LMK. This stuff is still new to me, and I'm trying to learn it before making a purchase. My only concern is being able to make this work with the PJ fixed at 14.5 ft. Because that's the physical closest I could move it without running additional wires, and I'm thinking I shouldn't have to with the zoom capabilities of the 8350. But I've been wrong twice before so... :D ;)


Edit:
Let me ask you guys something else: IF I forked over the money to have the ceiling and walls painted to match the rest of the room (dark brown), would that solve my problems, allow me to get a standard white screen, and ultimately get a better picture without sacrificing size? Or will I pretty much run in to the same kind of issues anyway? I may be able to get the paint job done for a few hundred, but I only would spend that IF the benefit is there. I'm running on the ragged edge of my budget right now with Christmas right around the corner so I'm watching every dime I spend at the moment. IOW, is the cost to benefit value of painting the room made up in parts (ie; projector life, screen material)?
 

·
Registered
Joined
·
43 Posts
@Erin H,

My room is quite different to yours, but does have white walls and ceiling. With the testing that I did, the improvements that come from eliminating reflections rather than trying to some how avoid their effects is enormous.

My personal opinion is that you'll have a vastly superior image after getting rid of the white walls and ceiling than you could ever achieve with a screen alone; painted or otherwise, including the most expensive commercial offerings!

Take a look at my thread if you'd like to know more about my thoughts, and plans so far. I still haven't chosen a screen paint yet, but I'm already very happy with my BOC screen, now that I've toned down the reflections.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #15
Well, I called a painter. If the quote isn't too bad I'll have the room painted. If it is, then I'll just have to consider my motives.

Still have to buy a dang screen. Lol.

I think ok going to go ahead and work on a frame in the meantime. I know I'm doing 110". It's just a matter of screen material. So knocking the frame out will at least let me make some progress while I wait, should the screen material not be purchased for a while.
 

·
Registered
Joined
·
290 Posts
Discussion Starter #17
If I can afford to have the paint done, would you guys opt for a darker color than I already have? I'm not sure the wife would go for it, so if the current dark brown will suffice then great. But if not, are we talking going to something like black?

Mechman, unfortunately that Carada would blow my budget to smithereens. I'd allotted $200 for a DIY budget and any paint job would put me further in the hole making an $800 screen insurmountable. :(
 

·
Banned
Joined
·
14,914 Posts

·
Registered
Joined
·
290 Posts
Discussion Starter #19
Got the paint quote. Picking up the paint today. Should be painted soon. Maybe even Friday if they have a chance to swing by.

Now I get to shop for a white screen. :)
 

·
Registered
Joined
·
85 Posts
Did a bit more reading. As I understand it, unless I paint, my only real option is a gray screen with a low'ish gain value, around 0.8 or so. This would mean more light is being absorbed by the screen, so less is being thrown "back out there" in to the room, helping with reflections off the ceiling, but that also means the PJ will need to burn brighter to increase the overall brightness.
Keep in mind, a brighter projector showing 12-14fL on a 110" flat gray screen will light up the whole room just as much as a dimmer projector showing 12-14fL on a 110" flat white screen. The only reason a gray screen would lower your amount of light reflecting around the room is if it is allowed to make the image dimmer (so you'll see less fL) or if you're keeping the same fL by going smaller (rather than using a brighter pj or similar option). A screen with a tighter cone might help tame its room-lighting abilities too.

Burning brighter against a dimmer screen will light the room just as badly. It is, however, better able to handle a bit of ambient light in the room so you might not be as bothered by the room's glowing from the PJ.

Edit: I'm slow. Please post more pictures once it's painted, that's a nice looking room.
 
1 - 20 of 21 Posts
Top