projector display with lights on

Discussion in 'Displays' started by lee w, Aug 3, 2004.

  1. lee w

    lee w Auditioning

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    Hi all.

    I am thinking of upgrading from a rear projection TV to a front projector. I am looking at the InFocus 4805 with a 80"x45" screen, either a De-Lite Matte or Cinema Vision. The screen will be 14' from the seats.

    I will be using this in the living room that has some ambient light that can be controlled to some extent with blinds.

    My questions are:
    1. Will I have to watch TV in the dark or low light levels just to see the picture? We have recessed spot lights on dimmers.
    2. Will diffused ambient light wash out the picture?
    3. Can anyone recommend a good screen for this application?

    The missus will hate sitting in the dark all night just to watch T.V. All movie viewing would be done at night so not a problem for the main event.

    Any advice from those with experience would be appreciated.

    Thanks,
    Lee.
     
  2. John F. Palacio

    John F. Palacio Supporting Actor

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    All front projectors users have to deal with the fact that the darkest black they will be able to see is that of the screen reflecting whatever ambient light there is.

    This almost demands total darkness. That's why movie theaters show in almost total darkness.

    Your tolerance to some ambience lighting will be hard to to predict. One way to gauge this would be to borrow a small-sized version of the screen you plan to use and place it in your room. With no projector look at the screen. That is the "blackest black" you will be able to see under those lighting conditions.

    Hi-gain screens do better. The higher the gain the blacker the blacks with ambient light.
     
  3. Neil Joseph

    Neil Joseph Lead Actor

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    The higher gain screen will give you a brighter image in ambient light than a lower gain screen will, but at the expense of making blacks appear more gray. I experimented a lot with this when I was looking for a suitable screen surface colour... white vs gray vs silver and opted for the silver/gray which does not reflect as much room ambient light but also helps with the contrast ratio.

    For me, I am a lot more picky when it comes to watching my movies than I would be with TV so a little wash-out would not bother me too much for TV viewing but when it comes to watching dvd's then I am a lot more picky.
     
  4. lee w

    lee w Auditioning

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    Thanks for the replies.

    Okay, so a high gain screen will be better for ambient light but how will it look in the dark?

    How much better would a Matte or Grey screen look due to the better dark colors?
     
  5. John F. Palacio

    John F. Palacio Supporting Actor

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    A high-gain screen basically reflects more light towards the viewer (narrower reflection pattern). Because of the way this is optically accomplished it will also reflect less light that does not originate form the projector's angle (ambient light). That's why they look dark gray or silver(hence the term "silver screen") instead of white.

    Theaters use high gain screens almost exclusively (this prevents light reflecting off the walls and ceiling (aside from providing a brighter image) so the only tradeoff is if you are going to have viewers at extreme angles.
     
  6. ChrisWiggles

    ChrisWiggles Producer

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    The best solution is a bright projector on a gray screen, or better yet a RP setup. I don't know when high-gain screens in ambient light environments became a good idea...
     
  7. lee w

    lee w Auditioning

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    ah, I now understand how a high gain screen works and why this is better for higher ambient light conditions, thanks John. But this is at the expense of lighter blacks, right?

    As we only have a single couch directly in front of the screen, I am not worried about the reflection angle.

    Would you consider the Infocus 4805 to be a 'bright' projector, and combined with a grey screen, would this work well in medium lit rooms?

    Thanks for the help.
     
  8. DaveGTP

    DaveGTP Cinematographer

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    I would say no. I've got an Infocus X1. A lot of questions keep coming out for using FP in lit rooms. No. It will look like crap. Watchable, maybe...at least, bright stuff. Anything with blacks will have them totally washed out.

    Now, just a bit of lighting? Like a really dim lamp, or a dimly lit room. Certainly. Medium lit? Personally, I don't think so. Perhaps tolerable at best. A high gain screen may help, but still...

    Anyone who doesn't want to sit in the dark to watch TV shouldn't be trying to watch it on a projector. It sounds like you should keep the RPTV for her daily TV watching and get a pulldown screen to use for movies at night.
     
  9. John F. Palacio

    John F. Palacio Supporting Actor

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    True black is no light at all so it will not be affected. Lower grays will be "brighter" along with the rest of the image but that can be adjusted with proper settings of "contrast" (for proper white level) and "brightness" (for proper black level).

    I have no info on the In Focus 4805 so can't comment there.

    I have to agree with Dave GTP that:"Anyone who doesn't want to sit in the dark to watch TV shouldn't be trying to watch it on a projector"

    Front projection that is.
     
  10. ChrisWiggles

    ChrisWiggles Producer

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    Yes a high-gain screen will be at the expense of elevated blacks. John is incorrect, we're not dealing with CRTs here. A digital projector cannot produce black, only a dark gray, and as such it will be brighter, along with everything else, on a high-gain screen. I reiterate my point that you should be watching with a light cannon on a gray screen, this is the best solution other than going RP, which is usually not feasible for most users. Your black will be defined by the projector and your choice of screen material, added with an option of using an ND filter, and whatever combination of those you choose. Your whites will also thus be defined within the limits of the projector's CR, which you will want to maximize.

    I don't agree with the notion that a high-gain screen is preferred in an ambient light environment.
     
  11. John F. Palacio

    John F. Palacio Supporting Actor

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    Put a NO (unity) gain screen (pure white) on an environment with any kind of ambient light and see what happens. A gray screen looks gray because it is reflecting less ambient light than a white screen. So this leaves no doubt about what I am saying.

    With light comming from the projector, however, it will be brighter than the white screen at its optimum viewing angle.




    So you and I, Chris disagree on EVERYTHING!!!!!!!!!

    A high gain screen gives you more intensity at a narrower viewing angle so to make blacks or dark grays as they were with a lower gain or no gain screen all you need is to "throttle down"!
     
  12. ChrisWiggles

    ChrisWiggles Producer

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    You are right that a gained screen, compared to a diffuse screen, is better. However, i don't feel that it is the preferred option for ambient-light environments. In the days of CRT, light output was a big limitation, so high-gain screens with narrow viewing angles worked best. Gray screens were not an option. Today, gray screens in conjunction with a very bright digital is probably a better combination in achieving a good picture in an environment of ambient light. The projector will overpower the room lighting to a much larger degree compared with a dimmer projector on a high-gain screen. Gray screens like the Grayhawk have become popular for this reason, as well as for improving viewed black levels. Furthermore, they also help at increasing the ANSI contrast by again minimizing the impact of light in the room, this time not ambient light, but rather light spill back onto the screen.

    If I had to choose among projector implementations, a RP setup is the best in an ambient light, followed by a very bright digital on a gray screen, followed by some projector on a directional-gain screen.


    I don't know what you're getting at here. You have limitations with the projector, you can't just "throttle down" the projector, its on/off CR range and output paramaters are defined at the projector unless you alter that with a ND filter(which only affects light output, and slightly ANSI CR), which may be desirable on a high-gain screen, but again you are then reducing the light output compared to the room, so this reduces the benefit of a high-gain screen, which is not that much to begin with.

    A high gain screen won't net you that much benefit with ambient light unless you plan the placement of lights carefully, and use a screen with a hellish viewing cone. Clearly the best way is to use screen materials that do not reflect ambient light back into the room, which is best done with a rear-projection screen, or a very very low gain gray screen used in conjunction with a very bright projector which is now possible with today's digitals (this was not an option in the days of CRT). The added benefit of the gray screen is improved ANSI in a dark room.
     
  13. lee w

    lee w Auditioning

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    Thanks for the input guys.

    I'm still a little confused.

    Firstly, what is a 'light cannon'?

    Secondly, what output level is considered high? The 4805 @ 750 ANSI lumens on a 92" 16:9 screen will give 30 foot-lamberts. Where would this be on a scale? (if there is one)

    Do both you guys agree that a grey screen would be better than a high gain screen for dim-medium lit room with this set-up?
     
  14. ChrisWiggles

    ChrisWiggles Producer

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    A light cannon, is just slang. Just a REALLY friggin bright projector [​IMG].

    Screen choice is fairly subjective with digitals, so it depends.
     
  15. Brandon B

    Brandon B Second Unit

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    Chris, you're missing a point as well. A gray screen makes ambient reflections darker, but it also makes your projected image darker in an equivalent proportion. It does not improve your contrast with ambient. It merely improves your black levels. The whiteness or grayness of your screen is irrelevant to improved contrast under problem ambient conditions. It is the gain and directionality of the grayhawk that yields any improvement in contrast lost due to ambient, not its gray color.

    A high gain screen can be an improvement in high ambient conditions. One very good example is the Da-lite High Power. It is a white (not gray or silver) 2.8 gain retro-reflective screen.

    Any ambient light striking it is preferentially reflected back at the source. So the ambient souces will be reflected more back a their source than at you. If your ambient light source is behind you, this will make matters worse. But if it is to the sides, it will improve the situation.

    It will, as you note though, give you grayer blacks at night when you have light control.

    BB
     
  16. ChrisWiggles

    ChrisWiggles Producer

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    I never made the claim that gray screens will improve your on/off contrast ratio. They do not. With a limited on/off CR of a digital projector, your screen choice determines where that 'slice' of CR lies. You can go low-gain to improve blacks at the cost of whites, or higher gain for a punchier brighter picture at the cost of worse blacks.

    What I said was that gray screens can improve your ANSI contrast, not on/off.
     
  17. Brandon B

    Brandon B Second Unit

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    Ah. Sorry, didn't read closely enough.

    I was reading your statements that high gain screens are worse for ambient light as a statement of fact, not preference, when I'd say it is the latter.

    BB
     
  18. Maurice B

    Maurice B Extra

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    Guys, there are viable alterantives. Sunlight? No way. Normal ambient light from lamps or properly mounted Can lights? You betcha.

    Between the developement of some special DIY screen applications, and the judicious use of proper Black Out trim, one can achieve an excellent image in low room lighting. A DIY screen that delivers higher than 1.5 gain, enhances perceived contrast levels, reduces SDE and Video artifacts, provides a 170 degree plus viewing cone, and costs a DIY'er less than $150.00 in materials, is not a dream, but a reality.

    Light Fusion, the use of a 1/4" x 4x8 or 5x8 Plastic Mirror covered with a Translucent white paint mix is the answer. the only answer to every one of the above desired Screen atributes. Would that it be really easy for any to produce, now that would be revolutionary. But no, it does require some work ethic, special materials, and preferably a HVLP sprayer, although some have rolled on a Mirror with success.

    I'm going to be posting a new Thread soon, complete with instructions, places to acquire materials, and links to specific suppliers. It would already be up, but the "Post no URLs" rule for new members effectively wiped out a two hour composition a few minutes ago[​IMG]
    (that has now been fixed)

    So watch for it, and meanwhile, go to my gallery in "Screen shots, and check out the offerings,
    http://www.hometheaterforum.com/gall...n-Screen-shots
    You'll find varying degrees of Ambient light shots, as well as one's taken in total darkness, Check 'em out and let me know what all ya all think.

    Pj on most was a SE 50-HD DLP (1280 x 768 res) w/1000 lumens. Camera was a 4 yr old Toshiba 4 MP set on Auto Exp / Auto Focus. NO post processing done except resizing down from 2400 x 1800 Enjoy.

    Mississippi Man
     
  19. JohnEF

    JohnEF Stunt Coordinator

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    I tend to agree that a gray screen with a bright projector is a viable choice, at least for me. Da-Lite's HCCV is a gray screen with 1.3 gain which is what I got with my Infocus 5700 which has an extra bright mode when you have ambient light (let's say having a super bowl party where you need enough ambient light to ensure people aren't spilling beer all over your furniture).

    Of course the best viewing is in a darkened room but it's nice to know that you have an acceptable picture when you raise the light's.

    Of course there are other issues that affect room light such as color of walls and ceilings, colr of carpeting, etc.

    John
     
  20. John F. Palacio

    John F. Palacio Supporting Actor

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    Looka here Chris since you seem to love to argue:
    I never said that FP was the preferred setup to use in a situation with ambient. Direct view CRT or plasma would be follower by RP. I just said that if the user was set in using such a setup then a high gain screen would work better. OK?

    Having said that I want to say I am out of here!

    BTW "throttle down" means reducing output of projector by whatever means you prefer.

    And yes a high gain screen will work better in a lit room because it limits the effect of the ambient light reflecting off the screen, while increasing output from light emanating from the projector. This is not theory it is a fact!

    Adios!
     

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