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I am an absolute newbie to the front projector world and have been reading several pots in these forums to begin to educate myself. I have seen several comments that talk about masking a portion of the screen. For exemple, when you view a 4:3 picture on a 16:9 screen.


Could anyone tell me why you need to mask a screen?


Links to posts or sites that give more details would be appreciated.


My apology if this is a stupid question, but like I said at the beginning I am just beginning to educate myself.
 

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You never have to mask, however masking a picture (giving it a frame if you will) gives the presentation a much more professional look. A black border simply looks better around a picture than nothing.


The issues are when you go from 2.35, 4:3 and 16:9 these all use different dimensions so the framing needs to be different. The frame is called masking. Masking can be done will all types of materials. People try everything under the sun to invent new ways to make masking easier when using different screen dimensions. And it's not easy...
 

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Quote:
A black border simply looks better around a picture than nothing.
I don't agree with this statement. As someone who's had a commercial screen with a black border for over 4 years and is now using a DIY screen w/o borders I can say that I prefer the borderless look.
 

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As Horrorscope said, the masking helps frame out the picture so that the viewable area contains only the picture. One of the benefits of having a border is that it improves your perception of the contrast ratio. Also, without the masking, if you are watching material with a different aspect ratio than your screen size, the unmasked area will be gray. It's like if you watch a widescreen movie on your regular 4:3 tv set. You get black bars on the top and bottom. To some people, seeing those black bars is kind of distracting.


If you go to watch a movie at the theatre, you may also notice that the curtains open or close a bit before the movie starts. Same thing. They're masking the screen so you don't sit there and wonder why the picture doesn't fill in the entire viewable area.
 

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All of the screen manufactures say it helps in perceived contrast ratio of the image. It does.

More of your attention is focused on the image as opposed to also adding outside information (light colored walls,paintings, anything to draw the eye away form your concentration on the image)


Best would be a completely black wall with your image in the middle.

Don't underestimate how much better the picture get's in this arrangement, the problem is very few ever go all the way and miss out on seeing what the difference is.


David
 

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In my setup I find that the absence of the border improves perceived contrast. My front wall is mostly black with a little bit of burgandy thrown in. The sidewalls are also black (upper) with burgandy lower. If I put an image on the screen that is not the same size as the screen itself, I cannot tell where the onscreen image ends and the unused portion begins as there is _very_ little if any ambient light being thrown back at the screen. With this setup, the black bars on 2:35:1 material do not have a black border to contend with which will always be blacker than any black my PJ can 'not' put out.
 

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Quote:
Originally posted by Mancubus
In my setup I find that the absence of the border improves perceived contrast. My front wall is mostly black with a little bit of burgundy thrown in. The sidewalls are also black (upper) with burgundy lower. If I put an image on the screen that is not the same size as the screen itself, I cannot tell where the onscreen image ends and the unused portion begins as there is _very_ little if any ambient light being thrown back at the screen. With this setup, the black bars on 2:35:1 material do not have a black border to contend with which will always be blacker than any black my PJ can 'not' put out.
Now wait just a darn minute. Your whole front wall is creating the same effect as a border. In your case, the entire wall is a giant black (and burgundy frame). If that wall was white, I'm guessing you would prefer a black border.


I prefer a border as well (unless the entire wall behind it is black -- which would also do nicely).


If you do complete masking, you would never see those 2.35:1 borders you speak about as well. I prefer NEVER to see black bars -- side or top. For whatever reason, they don't appear black enough. I've even seen scenes where the black in the scene appears blacker than the border! What's up with that? (fyi: Star Trek Nemesis space scenes are a good example of this phenomenon).


Seeing black bars is kind of like looking at an image through a crack in a fence vs. just looking at the image.


gp
 

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Quote:
Now wait just a darn minute. Your whole front wall is creating the same effect as a border. In your case, the entire wall is a giant black (and burgundy frame). If that wall was white, I'm guessing you would prefer a black border.


I prefer a border as well (unless the entire wall behind it is black -- which would also do nicely).


If you do complete masking, you would never see those 2.35:1 borders you speak about as well. I prefer NEVER to see black bars -- side or top. For whatever reason, they don't appear black enough. I've even seen scenes where the black in the scene appears blacker than the border! What's up with that? (fyi: Star Trek Nemesis space scenes are a good example of this phenomenon).


Seeing black bars is kind of like looking at an image through a crack in a fence vs. just looking at the image.
Actually, with the light being thrown from the screen coupled with the fact that the screen itself sits roughly 2 inches in front of the black/burgandy wall, the picture appears as though it is floating in the air causing whatever is behind the image to disapear, much like if you were to gaze into the headlights of a car on a dark street, your eyes adjust to the light source causing the surrounding area to become darker.


The blacker than the border look that you're seeing in 'Star Trek Nemesis' is perceived contrast. Your brain is fooling your eyes into thinking that the black in the image is blacker than it really is.


Here's an intersting demo of perceived contrast:

http://www.michaelbach.de/ot/lum_con...ast/index.html
 

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Quote:
Originally posted by Mancubus
Actually, with the light being thrown from the screen coupled with the fact that the screen itself sits roughly 2 inches in front of the black/burgandy wall, the picture appears as though it is floating in the air causing whatever is behind the image to disapear, much like if you were to gaze into the headlights of a car on a dark street, your eyes adjust to the light source causing the surrounding area to become darker.


The blacker than the border look that you're seeing in 'Star Trek Nemesis' is perceived contrast. Your brain is fooling your eyes into thinking that the black in the image is blacker than it really is.


Here's an intersting demo of perceived contrast:

http://www.michaelbach.de/ot/lum_con...ast/index.html
And, if you look at the lights in the daytime, they won't have the same intensity. Plus you will still see the surrounding scenery during the day. You have not demonstrated why having black around a screen doesn't help. In fact, you're really helping to support the original point of this thread.


Also, even if the black space in "Nemesis" is a perceived illusion, I won't be training myself to tell the difference. (In fact, my guess is the the space black has a little more blue which actually may make it appear darker). In either case, I still think that a true black border (or surround) provide a better viewing experience. And, I support the recommendation of this thread. Masking and borders are a good thing. And, the bigger the better.


gp
 

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I am not arguing that you do not need a black border around the screen. I am saying in my case I prefer not to have a black border,( i.e. 2" strip of black around the screen). My original and continuing point was that in my setup I prefer the absence of the black border around the screen. As a frame of reference, my old set up had a black wall WITH the black border for over 4 years. To my eyes borderless with the black/dark wall looks better. Needless to say I was suprised as I was planning on installing it and decided not to after seeing the difference.


Are we clear?
 

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After my "conversations" with Mancubus, I would propose that the reason for masking (and/or borders) is to provide a more distinct separation of the viewing material from the surrounding environment. By doing this, the viewer has an easier task of becoming absorbed in the presentation.


Thanks Mancubus, I couldn't have made this statement without your lost in the headlights imagery!


gp
 

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Mancubus but what you are doing (which is a cool idea) is still creating a mask around the screen. Sure it's different than most but that's the part about everyone trying everything. But you do have a dark mask around your screen, it's the dark wall. Well unless I'm not understanding what you have.
 

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Yes, I do have a dark back wall without the 2" border on the screen itself. My old set up had a dark wall AND the screen with the black border. What I'm saying is, I prefer the dark wall w/o the border. Obviously, if you can't have the dark wall then having the border would be better.
 

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with digital pjs doesn't the perceived contrast get lower when you add masking or borders? I mean if your using something that absorbs light like duventyn you are getting a very black border or mask on the screen. When you see the black level that the pj is putting out compared right next to the black level reference of the border next to it can't you notice even more the limitations of your low contrast digital pj.


I agree that masking, borders, black walls, isolate the image so its all that your seeing but I think that w/digital pjs it would lower the perceived contrast instead of raise it. I think if you wanted to raise the perceived contrast you would want to make the area around the screen lighter. Maybe a light grey border, or even some bias lighting.
 
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