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I'm really considering buying a crt projector and I need to know a few things. One is brightness the other is screen size. What screen size can you get from your average crt projector and is brightness an issue?. I'm looking at a screen size of at least 125inches diagonal 16:9. From what I've read crt's are not bright machines. I have a pitch black room but only a white wall for a screen. I'm worried that the image will be too dull for my liking.


I've actually saw alot of crt projectors back in the laser disc days, I don't recall them being dull just too expensive to consider buying one.
 

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The amount of light you can send to the screen depends a little bit on the size of the tubes, CRTs come typically in 7, 8, and 9'' sizes.


In my opinion a 125'' diagonal for 16:9 is too large for a CRT. But many here on this forum would disagree.
 

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I'm running a G-70 at a 16:9 screen of about 115" diagonal (Parkland Plastics DIY screen).


If I had to do it over again, I'd probably make the screen slightly smaller, because I've seen what images can be produced on a smaller screen with more brightness, but no one who looks at my system will think, 'Gosh, that's kind of dim." I have almost total light control in the room, and the picture is stunning, even on DVD-based sources.


--Jim
 

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Most of the CRT PJ's you will find in OZ are 7"-8"tubed models from either NEC,SONY or BARCO

The recommended largest size screen to go for with this size tubes is a 100" diagonal 4:3 screen,the easiest way to set them up is using that screen size/ratio.

The width of the screen will remain a constant regardless of what format you project on to it.

The hight of the projected image will change within that 100" diagonal depending on the aspect ratio of the source material ,you will have varing amounts of black bars depending on the way the DVD is presented,just look on the back of the various DVD's to see what the different ratios are.

There are other methords of setting a CRT up for a particular aspect ratio but if think it would be better for you understood the basics first ,it's a solid grounding to base any future questions you might have.

Have a look at the FAQ's at this site,it should explain what you need to know.
http://www.crtprojectors.co.uk/general_faq.htm
 

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The easiest thing to do is to look at a 1000-1200 lumen digital projector at that screen size. A lumen is a lumen, and if a digital isn't bright enough at that size screen, then neither will a CRT.
 

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I run a Barco 1208/2 ( 8" 1200 peak lumen ) on a 160" diagonal 16:9 screen ( 12' x7' ). I started with just a white wall as the screen, then switched to CRT white screen goo. The room is totally light controlled, and the walls, celing, and carpet around the screen area is black. Even though the math shows that this should bounce less than 4fl, I find it satisfyingly bright ... to me, similar to a commercial theatre ( that always has some ambient light ).


While the white wall was OK, the inscreased gain of the screen goo really gave the pic more punch. The black around the screen area ( which I did after the Goo ) added even more punch.


Larger screen sizes require much more attention to setup, especially mechanical and electrical focus. I would only try this with an ES set. Also, scaling is critical to getting the optimal pic. I use an HTPC and Zoom Player. The scaling / sharpening filter has many options, and can give you a great pic if you devote a bit of time to it.


I also have a 1300 lumen digital. While it's very bright and sharp, I find the main theatre setup to be a much more pleasing pic.


Jonathan
 

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Quote:
Originally Posted by Curt Palme
The easiest thing to do is to look at a 1000-1200 lumen digital projector at that screen size. A lumen is a lumen, and if a digital isn't bright enough at that size screen, then neither will a CRT.
While a lumen is a lumen, if you use peak lumens for CRTs instead of ANSI lumens then you should take into account that calibrating a CRT to actually use those peak lumens means pushing the tubes pretty hard. And also can mean color skew with lots of bright stuff on the screen as one of the tubes hits its light output limit (usually the blue) before the other tubes. The CRTs I've seen setup by professionals have been calibrated more in line with the ANSI lumens rating than the peak lumens rating. And unfortunately going by specs for digitals can be misleading because some companies hit their specs and some exaggerate (especially at D65), so many people look for tests from other people or historical figures for companies to try to determine how bright they are likely to be. Just a couple of things to keep in mind.


--Darin
 

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Quote:
Originally Posted by Curt Palme
The easiest thing to do is to look at a 1000-1200 lumen digital projector at that screen size. A lumen is a lumen, and if a digital isn't bright enough at that size screen, then neither will a CRT.
Curt, keep your dPJ comparative analysis recommendations to yourself. :p :D


As usual, I agree with darin... ;)


IMHO, there's way too many variables to make that a useful relative comparison. Would the unseen CRT be using the same screen as the digital being used to assess brightness? Regardless of rated lumen specs, does the dPJ have a fresh bright bulb or one that has significantly dimmed after some use? What is the condition of the CRT? Is it properly setup or improperly overdriven?
 

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If I remember my trig, a 125" diagonal 16x9 aspect screen will be 46.4 sq ft.


Multiply your desired foot lamberts of light by the square feet and you will know how many lumens that you need.


This is true for a screen with a gain of one.


So desired 7fL * 46.4 sq ft = 325 lumens


7fL is not real bright.


There is a minimum light level suggested for movie theatures that I can't remember right now.
 

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Interesting. We measured quite a few various of levels of ft lambert's with Ken's pro meter this weekend at Cliff's. I'd call 7 bright enough. Certainly brighter than I've ever run (I bet I'm only getting between 3-4).


But IIRC, the theater recommendation is 11. Which would make sense, becasue Art gets 11 ft Lamberts from is 2 G90s... 5.5 each.


Despite the math and measurements and recommendations, it's still just another personal preference that you need to determine for yourself if it's acceptable or enjoyable based on your projector and your room's lighting environment.
 

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Why not a torus? Won't you get a big gain in brightness? Several people here have built them around 106" x 60". I'm still trying to find 9 foot plywood to do one.

Mark
 

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Quote:
Originally Posted by Clarence
Interesting. We measured quite a few various of levels of ft lambert's with Ken's pro meter this weekend at Cliff's. I'd call 7 bright enough. Certainly brighter than I've ever run (I bet I'm only getting between 3-4).


But IIRC, the theater recommendation is 11.
I get the feeling that most commercial theaters are running lower than recommendations. And many of them have lights on that make things worse.


What I have found in my testing is that I tend to be happy at about 6 with lights off and start to get unhappy in general down under about 4. And many people are surprised at how bright 6 ftL or so can look in a light controlled enviroment, as you alluded to. There are those who just like much brighter images and it is a personal preference thing largely though. I also believe that as people's eyes age their preference can go more towards brighter because of some loss of ability to make out details with dimmer images. I also think that cleaner sources and images can increase the amount of ftL that a person desires.


--Darin
 

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Quote:
Originally Posted by darinp2
I also believe that as people's eyes age their preference can go more towards brighter because of some loss of ability to make out details with dimmer images.
Yeah! Tell me about it. :( I'm 46 and find that fine print is REALLY tough in dim light. Heck! Sometimes it's tough in our bright Colorado sunshine. "Say son, can you tell me what this says?" Guess I have to break down and get those reading glasses. :eek:
 

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Quote:
Originally Posted by PAW
Yeah! Tell me about it. :( I'm 46 and find that fine print is REALLY tough in dim light. Heck! Sometimes it's tough in our bright Colorado sunshine. "Say son, can you tell me what this says?" Guess I have to break down and get those reading glasses. :eek:
Yep... I'm approaching 40 too fast... I had my first real taste of that last week in a hotel room. The message light was blinking on the phone. The printed text said "press 688 to retrieve messages". Even with the nightstand lamp on, I couldn't read the digits. I had to disconnect the phone and carry it into the brighter lights in the bathroom to read the numbers. :(


But I still run my laptop desktop at native 1920x1200.


I saw Casey's 3.1 gain torus yesterday from his XG. Cliff and I estimated 10 ft Lamberts.


Cliff and darin have seen Art's G90's at 11 fL. So they have a mental reference of the reference upper end of CRT brightness.


But I certainly think 6-7 is sufficient. With total light control, I don't find myself cranking up the contrast and brightness above norm.
 

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Quote:
Originally Posted by wvpinballguy
Why not a torus? Won't you get a big gain in brightness? Several people here have built them around 106" x 60". I'm still trying to find 9 foot plywood to do one.

Mark


I used 1x12" to put mine together.
 

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Quote:
Originally Posted by davidcrowe
I used 1x12" to put mine together.
Duh, I guess that would make it easy. I previously saw plywood mentioned, and was stuck on that idea.

Thanks, Mark
 

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I run my ECP 4500+ at about 130" diagonal in 4:3 and around 119" in 16:9. I have the ability to get about 1 more foot of width out of the picture and I'd go for it if it wasn't for the fact that the top of a 4:3 image would be on part of the ceiling afterwards. lol.


Right now I'm using a dark silver/grey screen (a bit less bright than white) that I was using to enhance the blacks on my X1 DLP and the CRT is plenty bright enough on it. Blacks are much better on it too. I actually can't decide if I want to go back to the white now since I can even watch in a little ambient light now.


Surprisingly, I may go with a grey/white striped screen that I designed on soft gloss photo paper. From all the tests that I did last night I've come to the conclusion, IMO, that it looked better than the pure white. It looked nearly identical in nearly every case except the blacks looked better and ANSI washout was much less on the grey/white than on the white (although not as good as my dark silver in this respect).
 

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Quote:
Originally Posted by Clarence
But I certainly think 6-7 is sufficient. With total light control, I don't find myself cranking up the contrast and brightness above norm.
Me too, if I recall, I measured 6- 7 ft / lambert with my Milori Colorfacts when I first got it. I run a Barco Graphics 808s on a 96" * 54" high gain CRT Goo screen. I actually find that it is too bright when transitioning from relatively low APL scenes to very bright white scenes like those in the Superbit Vertical Limit. I have a cave though - dark grey walls and ceilings and a large black throw down rug between the first row and the screen.


There was an excellent response in the letters section from Shane "Buetner" in a recent edition of the The Perfect Vision. The author of the letter was of the mindset - go big or go home. Shane B (a reviewer for TPV) responded to this and another related letter about how a great projector can become bad when using too large of a screen.
 
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