Screen gain vs lumen output

[electronbee]

I'll be getting a Panasonic PT-AE2000U projector. It has 1500 ANSI lumens but that will drop to between 345 to 390 lumens in the Cinema Modes and measured by Projector Central.

The projector would be a max of 14' feet from the screen but I'll probably have it closer to increase the overall brightness as I want the screen to be as wide as the projector and laminate would allow. Also, it'll be in the basement so I'll have total light control.

I was thinking of the Designer White laminate but would that gain of 1.24 be too much for people? I have not been able to find a rule of thumb or any calculator anywhere to help.

Thanks!

eb

[mechman]

eb,

Welcome to the Shack! Buy the DW! It's a great DIY Screen! It's probably the best solution that I've seen for a white screen.

I can't recall were the 1.24 gain number came from originally. I know that some of the numbers on a lot of DIY things were incorrect or measured improperly. That's why we're currently redoing all of the measurements that we possibly can.

Did you take a look at the Calculator over at Projector Central?

mech

[cynical2]

The DW is a great choice for a light-controlled room. I have the AX100U, which is about 25% brighter than your pj, and have seen several people talk about what a great match the AX100U is with the DW. Bottom line...I think you'll love it. It's a great neutral substrate (see testing results in the "Data" sticky). It's super durable, and obviously no paint is needed.

As far as a calculator...

You'll 1st need to decide on screen size

Then, take your lumens and divide by sq ft of the screen.

"Ideal" after that calculation will give you about 14-15 ft-L in a light controlled room. That's about what I run most of the time (in 16:9). In wide screen, I run a bit less.


If we go through that process backwards...let's say you want to target 15 ft-L.

Take your 375 lumens and divide by 15 to get: 25 sq ft. or 3600 sq in.

That's a 92" screen (45"x80").

So, if you want 15 ft-L your "best mode", you'd target a 92" screen if you have a gain of 1.0.

With a gain of 1.24, you can increase your area to 3600*1.24=4464 sq in...works out to a 102" screen (50"x89").

That being said, if that's not big enough for your liking...you have the option to run slightly below 15 ft-L of brightness, or running in other projector modes. For instance, your "normal" mode probably has twice the brightness. And, at least on my model, the normal mode is considered to still have very accurate picture quality.

Not a definitive answer...but some things to think about.

[wbassett]

Welcome to the Shack eb!

Here's a nifty little spreadsheet that also has THX and SMPTE standards included such as recommended viewing distances, recommended lumens and fL... it's a very nice little tool.

Also if you haven't seen this thread, here is one on Gain and other confusing topics. It can get a bit techie at times but I try to keep it somewhat understandable.

All in all though, Designer White is a very nice screen.

[electronbee]

I believe I got the DW gain of 1.24 from here on this site.

And, yes, I have used the Projector Central Calculator but I was looking at the wrong place and looked at the max room brightness versus the fL number. I do not know how I did that.

Oh, since we're here, how much of a factor is the color of the walls? They are a deep red right now. There's a white ceiling and a neutral colored carpet. The sides of the perpendicular walls will be pretty far from the screen if I am at 84" wide. But, I would not want to have a red hue or anything. Which is why I had asked about the Platinum. I should have mentioned that I guess.

Here is a link to the place I close on Nov 30th. The basement has the red walls. There is a small alcove you can kinda see in one of the pics but it is actually kinda small. You can tellmy how the desk consumes it. The basement pic where they had that flat panel makes the overall better arrangement especially with speaker placement.

Thanks!

eb

[wbassett]

electronbee wrote:

I believe I got the DW gain of 1.24 from here on this site.

And, yes, I have used the Projector Central Calculator but I was looking at the wrong place and looked at the max room brightness versus the fL number. I do not know how I did that.

Oh, since we're here, how much of a factor is the color of the walls? They are a deep red right now. There's a white ceiling and a neutral colored carpet. The sides of the perpendicular walls will be pretty far from the screen if I am at 84" wide. But, I would not want to have a red hue or anything. Which is why I had asked about the Platinum. I should have mentioned that I guess.

Here is a link to the place I close on Nov 30th. The basement has the red walls. There is a small alcove you can kinda see in one of the pics but it is actually kinda small. You can tellmy how the desk consumes it. The basement pic where they had that flat panel makes the overall better arrangement especially with speaker placement.

Thanks!

eb

The walls themselves shouldn't add a hue, but your eyes can 'sync' to them if they are clearly visible while a movie is on. This is much the same as why we use a black border for our screen border, it looks nice but also acts as a black reference point for our eyes.

Normally this isn't a problem unless the walls are some vibrant bright color and you have some lights on and can clearly see the wall color and the screen. If it's say a brick red or Burgundy it shouldn't be an issue. Other earth tone or colors that aren't bright and vivid should be fine too. The ceiling could be a problem, at least by the screen if the screen is closer to the ceiling like mine... here is a shot showing how much reflected light there can be from a screen with a bright projector...

You can clearly see the reflections from the screen on the ceiling and the adjacent wall. This will reflect back onto the screen to some extent. My projector is bright enough to over power it, but low Lumens could start washing out.

Even during the day you can still see how much is reflected onto the wall and ceiling.


With a movie playing though it's not as distracting as I may have made it seem

Now, this isn't Designer White, that screen is currently down and rolled up for storage but these demonstrate reflection well I think.

The PT-AE2000U is pretty close to my Lumen rating of 1700 Lumens so you'll have a similar experience. As much as I love Designer White, my room is not a dedicated Theater room with controlled lighting or a theater setting. My wife does like a room lamp on (I don't) and without a Theater setup with darker walls and ceiling, I was getting an enormous amount of reflected ambient light from the screen itself. It was like I had my low wattage room lamp turned on for all except the darkest of scenes. Although the experience wasn't awful, it wasn't what I personally liked. Now if you have a properly setup HT room, DW is absolutely fantastic and is a near D65 neutral white, in fact almost hitting the neutral tolerance. It really is a DIY white reference screen if you ask me.

I am painting my walls a slate gray but probably won't paint the ceiling. I may try Designer White again once I do that. I certainly do not want to sound like I am being negative on something I found and have promoted, I am just giving the pros and cons of it. For a dedicated room with light control and proper setup, it is truly fantastic. For a multi purpose room, that would be a matter of personal preference.

[mechman]

Who did the gain measurements? Garry?

mech

[wbassett]

Yeah Garry did them.

[electronbee]

I have another question. How do the laminate screens compare to manufacturer screens? As in dollar value. I know a laminate will not compare to some 2.8 gain $4k screen but how about to the several $100 ones? I'm asking as I have seen some "bundles" where I can get my projector, a screen, ceiling mount, and HDMI cable. The screen you get with those bundles is like a $299 MSRP screen or something I imagine.

I am merely curious.

Thanks!

eb

[cynical2]

electronbee wrote:

I have another question. How do the laminate screens compare to manufacturer screens? As in dollar value. I know a laminate will not compare to some 2.8 gain $4k screen but how about to the several $100 ones? I'm asking as I have seen some "bundles" where I can get my projector, a screen, ceiling mount, and HDMI cable. The screen you get with those bundles is like a $299 MSRP screen or something I imagine.

I am merely curious.

Thanks!

eb

EB,

Something like Designer White stacks up extremely well when compared to most commercial white screens (even quite expensive commercial screens). Enough people with a lot of experience reviewing both commercial screens and who have looked at laminates have come to that conclusion that I tend to think it's true.

If I were a betting man, I'd bet that most would enjoy the viewing experience of DW vs an inexpensive white commercial screen that comes in a pj bundle.

That being said, because I haven't done the comparison myself, I'm going to refrain from trying to draw specific comparisons. I think Mech and Bill can better give you specifics on what the advantages/disadvantages of a good laminate vs an inexpensive commercial screen would be. They have much more experience than I in making such judgments, and have both looked at commercial and laminate screen solutions.

[wbassett]

First, don't worry about gain unless you need it to bring your fL up to the required amount for either a light controlled room or one with ambient lighting. Gain has been over used and misunderstood in my opinion. It can be good, but also too much can have issues of its own.

Laminate screens- They far exceed those entry level screens you see on eBay and places like MonoPrice sell. I won't go as far as saying that are the same as top of the line commercial screens, but they perform as well as mid level commercial screens and may even be broaching the lower level high end screens that cost ten to twenty times more. There have been some direct comparisons to Da-Lite, Carada, and Stewart's ST130 and Designer White held its own against all of them. Some of the commercial screens had a very slight edge, but DW did well. Fashion Grey is also a great screen, but we've found another with a better color balance, that would be Platinum. It's a bit darker though but not much.

If the bundle you're talking about is the same price and the screen is thrown in as a freebie, then you might as well get it, but I don't think I would pay extra for a bundle package. Pretty much those screens are the equivilent of the free cables you get with a DVD player... people typically throw those cable out and use better ones.

For cables, check MonoPrice or RiteAV. I prefer RiteAV slightly over MonoPrice because when I placed my order MonoPrice didn't seem to have anything I was looking for in stock and RiteAV always has their cables in stock.

With 1500 lumens you really don't need a lot of gain unless you're going with a huge screen. If you're interested in a laminate screen, specifically Designer White, shop around for prices too. I've seen prices from $43 at a local lumber yard for a 4x8 sheet to in the $90's at Home Depot for the same thing, and the larger sheets are even more at the big chain stores. So like I said, check around and you can probably get a much better deal than at Lowes or Home Depot.

[electronbee]

Yeah, I won't be going with an enormous screen size as DW or Platinum will only come in a 4x8 or 5x8 sheet and I will be stopping there.

Thanks!

eb

[wbassett]

You can get them all the way up to a 5x12 size, but you're restricted to that 5' height.