Projector Questions

[Erman_94]

Hey guys, I will be incorporating a projector setup in the not-too-distant future and just wanted to gain as much information as possible before purchasing anything. I will use this thread to post my questions so that I don't end up making many different threads. I have received a lot of help thus far from forum members and was hoping to learn more. any help is appreciated.

1) Assuming that lighting is completely controlled (i.e. walls painted black, non-gloss paint, no windows etc.) is a higher gain (whiter) screen always better?

2) I think I get the idea that if i were to purchase a 2:35:1 screen i would use masking panels for 1:85:1/16:9 content to cover the black bars that would appear on the side. But with the 2:35:1 screen (using a CIH setup) what would happen if I watched movies that were 2:4:1? Wouldn't I get black bars on the top and bottom? Or would they be so small that you couldn't see them?

3) Also I see there are lots of 'curved' screens now, what determines what radius you should get for a 'curved' screen? How would you know if you needed one/what are the benefits to a curved screen?

Thank you all very much in advance!

[MADNOD]

nice questions, no answers from me , so experts please bring it on.

[Jeremy1983]

I can only answer #2. I have a 2.35 screen and some films that are 2.39 or 2.40 have slight black bars on top and bottom. It's not really all that noticeable though. I would suggest making a 2.40 screen if it concerns you.

[Erman_94]

Originally Posted by Jeremy1983

I can only answer #2. I have a 2.35 screen and some films that are 2.39 or 2.40 have slight black bars on top and bottom. It's not really all that noticeable though. I would suggest making a 2.40 screen if it concerns you.

thanks for the reply

but wouldnt making a 2.40 screen now give me black bars on the side for 2.35 content?

im assuming there is no perfect solution to this...

[Deciazulado]

Originally Posted by Erman_94

1) Assuming that lighting is completely controlled (i.e. walls painted black, non-gloss paint, no windows etc.) is a higher gain (whiter) screen always better?

A higher gain will give you a brighter image from the projector and reject more of room flare as that's coming from other directions. Gain is separate from color: A darker color screen will also reject more of the room light but to compensate you'll need higher projector output. Two ways to skin the cat.

(So a high gain darker grey screen would do both approaches simultaneously)

black room + high gain + dark screen = all -> maximizing contrast.

But the first step is to make the cave black so you have very little light reflecting back onto the screen in the first place.

2) I think I get the idea that if i were to purchase a 2:35:1 screen i would use masking panels for 1:85:1/16:9 content to cover the black bars that would appear on the side. But with the 2:35:1 screen (using a CIH setup) what would happen if I watched movies that were 2:4:1? Wouldn't I get black bars on the top and bottom? Or would they be so small that you couldn't see them?

Yes that happens. By the way, having measured hundreds of actual "Scope" BDs, I've found some ranged from 2.02 to 2.42 (Scope ratio has been 2.39 for the last 40 years)

The solution to this is either have a zoom lens and make tiny adjustments for each, or project the image slightly bigger than the masking, for all of them, so the screen is always filled (in other words: ovescan). Or live with tiny edges

Also be aware that if you use anamorphic software scaling, if it's true 1.33x/0.75, the 1080 x 1920 panel would display from a 2.37 area (2.37 = 810 x 1920, 810 x 1.33 = 1080) .


Also remember that there are wider ratios than 2.39, like 2.55 and 2.75, with a a few dozen movies ever made on those. (About 4 BDs released so far)


Which bring me indirectly to curved screens

3) Also I see there are lots of 'curved' screens now, what determines what radius you should get for a 'curved' screen? How would you know if you needed one/what are the benefits to a curved screen?

Thank you all very much in advance!

A curved screen seems more encompassing, as the far away sides of the image are brought closer to you so they start looking to be the same size as the center (You might not think of it but with big enough flat wide screen it starts to happen that the sides start to shrink visually). Depending on the size, seating distance and the curvature of the screen, it can even make the screen look wider still, since the curve starts to surround you and when you move your head side to side slightly you're still met with image. Like in real life.


Curving the screen also redirects the light towards the center specially with high gain screens (But this can also redirect some of the left side light to the right side specialy with full matte screens) (<the reason why the 146º CINERAMA curved screen was composed of thin strips)*

The curvature chosen could go from very slight to one where your seat is the center of a semicircle made by the screen and your sitting distance is the radius of the circle.

*As an extreme example of curved screen if you wanted to reproduce at home the CINERAMA effect with the 2.89 wide transfer of How the West Was Won, would be to sit at 9 feet from the screen, and with your seat being the center of a semi circle made by the curved screen, to have a 153º field of view curve (2.89's disc extra width over original 2.59 146º) with 8 x 24 feet semi circular screen

A more normal 2.39 screen of the same curvature as the CINERAMA one would be approx 4.5 x 11 and just cover a paltry 68º

Happy New Year!

[Erman_94]

Thank you very much, deciazulado. That was a very informative and useful post. I definitely learned a lot from it.

I had a few follow-up questions:

1) The room will be 100% light controlled (i.e. pitch black with very dark walls/ceilings, carpet and furniture)...so wouldn't I get the greatest benefit from a white screen with a high contrast projector? I know you said that a dark room, dark screen and high gain gives you greatest contrast, but if my room is a dedicated, light controlled environment, I wouldn't need the dark screen, correct?

If so, is the following the best setup for me: Dark room, high gain, white screen and high contrast projector?

2) You mentioned using the zoom lens on the projector to eliminate the bars, but isn't that similar to "Pan & Scan"? Would this distort the image and result in some of the image being cut-off?

3) In a nutshell, the curved screen will give you a more encompassing image as it will make the ends of the screen seem closer. Is that right? Also, the radius of the screen will depend on my seating distance?

Again, thank you for the great and simple post for an amateur like myself.

[Deciazulado]

Originally Posted by Erman_94

1) The room will be 100% light controlled (i.e. pitch black with very dark walls/ceilings, carpet and furniture)...so wouldn't I get the greatest benefit from a white screen with a high contrast projector? I know you said that a dark room, dark screen and high gain gives you greatest contrast, but if my room is a dedicated, light controlled environment, I wouldn't need the dark screen, correct?

If so, is the following the best setup for me: Dark room, high gain, white screen and high contrast projector?

Yes if the room is totally black with no other sources of light in the room apart from the movie image. The light falls on the screen it bounces to the walls and bounces from them back to the screen. If there's no other lights that's the only source of flare. As the walls are black, the light bouncing to the walls is absorbed greatly (that's why dark walls in the room are so important ) before bouncing back to the screen. Since this light comes from the projected image, in this case dimming or brightening the image on the screen (be it by a grey or white screen or by increasing or decreasing the projector's light output) doesn't change the contrast as everything is a function of the light from the image itself.

On the other hand if you had some other light source in the room, the darker grey movie screen reduces this lamp's or window light falling on the screen or bouncing from the walls onto the screen (even if the walls are black) if you then increase the projectors output relative to the room lights. (That's why having no other sources of light in the room is good: Ratio of light bouncing from image on the screen to light bouncing from other light sources on the screen = infinite ).

A high gain screen redirects the most light from the image towards you (and the wall behind you ), increasing the image light output, and less to the side or even ceiling/floor walls (depending on the design). So any light bouncing from these side walls falling on the screen is also lower relative to the image, increasing the contrast ratio between image and room flare.

Just be careful to check the high gain screen's gain is not so high it creates a hot spot from your seating position.

(look at screens in real conditions )

2) You mentioned using the zoom lens on the projector to eliminate the bars, but isn't that similar to "Pan & Scan"? Would this distort the image and result in some of the image being cut-off?

Well depends if your screen is as wide as the widest image you throw on and vary the zoom on each, or if you use, lets say only 2 fixed zoom positions (like 1.78 and 2.37 in an anamorphic lens switch set up) to show everything even if they have minute variations..

Let's use a 2.40 screen as example. You play the Wizard of Oz so the image's 1.37 height fills the height. No Pan scan. You switch to Heroes Season 1 , 1.78, has the same height on the BD frame, same zoom setting, no pan/scan. You show Angel Heart's 1.85 image, you zoom in a smidge so the 1.85 height fills the height, no pan/scan. You play the Last Emperor's 2.00 image you zoom more so the 2.00 height fills the height, no pan/scan. You play The Sand Pebbles' 2.35 image, you zoom a little more so the 2.35 image fills the height, no pan/scan. You play WALL•E's 2.39 image, you zoom very slightly more so the 2.39 image fills the screen, no pan/scan.

Now only in the case of if you played anything wider than the 2.40 screen, like 2.55, then you either letterbox that or would zoomed in to crop the sides to 2.40 to fill the screen height.

On the other hand if zooming slightly each time, lets say from 2.33-2.42 each for Scope movies is a hassle the only other thing is to use one major setting for Scope movies and chose one ratio (like 2.40) for the screen with the mask that way, and then select a zoom/projector position that fills it with all these disc's minute variations So you have a 2.40 screen and project a 2.40 disc filling it, well a 2.35 disc fills it too but loses 2% of the height.

3) In a nutshell, the curved screen will give you a more encompassing image as it will make the ends of the screen seem closer. Is that right? Also, the radius of the screen will depend on my seating distance?

Yes, it won't make the screen center seem closer, but will make the width scope more encompassing, slightly more involved. Also since the sides are pointing at you more they might be less light fall off from the sides. The curvature of the screen will look different depending on the sitting distance and the size of the screen, if you have a very curved screen and sit far far away then the screen will look too curved and the effect doesn't work. Thats why I said the most extreme screen's curvature should be the one where your seat is the center of a semicircle drawn by the radius being the distance from the screen



You can sit closer or have a screen of less curvature till it reaches flatness.

Also if you get a curved screen it might help a little if the screen has higher gain that a matte screen and/or is darker than white to minimize flare light from the extreme left side of the screen falling on the extreme right siide of the screen.



(The extreme right light doesn't fall on the extreme left unless you're south of the equator.


I'm kidding about that of course.)

[Erman_94]

thank you very much, deciazulado.


i have learned so much already with your informative posts.

there is definitely a lot to consider, but it will be worth it for the pj setup IMO


thanks once again for all the effort you have put in

[Fors*]

Originally Posted by Deciazulado

Happy New Year!

That is an amazing pic and view of a curved screen.....just awesome!!