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Maximising image contrast - Part 2

Discussion in 'Projectors' started by jacked, Feb 22, 2012.

  1. bravogolf

    bravogolf Member

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    I've been making panels for mine but boy am I not practical. It takes me ages to do a panel and I think I'll leave the vaulted (attic conversion) ceilings along, I spent the morning making crappy angular ones that I'll throw away!
  2. gingerone

    gingerone Member

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    Cant really go down the route of building frames to be honest.
    Ive just put fabric up along one wall and it works really well. Just makes it glaringly obvious how much i need to do the other walls and the ceiling though:(
  3. Pecker

    Pecker Well-Known Member

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    Yes, I know. That's what I said.

    The point is you'll get a lot of people telling you the main problem is light bouncing off the walls back on to the screen. I actually think it's the light getting in the eyes, combined with the distractions this cause, which are the bulk of the problem.

    For a long time discussion in this area has been entirely about light reflections from screen to wall then back to screen at the excluion of all else.

    Just trying to open things up a bit.

    Steve W
  4. Pecker

    Pecker Well-Known Member

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    Sheep, this is what I've wanted to do for some time, but the other half doesn't listen. Maybe I can show her these pics to explain what I mean.

    To be fair, I think you're helped by the fact that you've put your screen in front of the window where you acrtually need curtains anyway. My curtains would have to be purely for the purpose of darkening the walls around the screen.

    Steve W
    Last edited: May 6, 2012
  5. sheep

    sheep Member

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    It actually looks better than the pics show mate. Honestly my wife was dead against it but I promised if she didnt like the ceiling I would re-paint it ;-). She now thinks it looks really good(thank god lol) I did have my doubts to how much difference all this blacking out would make but it really does make a huge difference.
  6. bravogolf

    bravogolf Member

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    Hehe, girlfriends eh? My fiancé surprisingly thought the Devore sample was nice but later that evening, she'd obviously been thinking about, wanted to look at alternative colours! I think she settled on purple! When I explained the purpose of it she simply rolled her eyes :) My plan for painting the room is to wait until today when she's working and do it all day :D probably not the most communicative way but I got up early and finished a shrubbery and cut the grass so she'll be happy :p
  7. Gary Lightfoot

    Gary Lightfoot Active Member

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    That's because it is - and it's a very real problem - you can both see it and measure it with instruments as has been explained many times here before. A bad room can allow just 50:1 ANSI contrast at the screen, whereas some treatments near the screen can increase it to around 200:1.

    A bright room may cause a bias lighting effect on the eye - that's often useful with small tvs to help reduce fatigue on the eye but not wanted with a projected image (that's also been discussed here). If that's happening then again, you may want to darken your décor. Even with direct view tvs and unwanted light coming in from a window you may want to draw the curtains.

    Unless you have mirrors in the room, the light bouncing from the screen will be strongest nearer the screen (walls, floor and ceiling), so treatments there will have the biggest effect. Ideally you need to do the whole room though.

    Even if you were able to make an effective toilet roll around your eyes to stop reflections from your walls, it still won't stop the image degradation due to light from the walls reflecting back onto the screen.

    Maybe a peep-hole in a wall would work if your main concern was the effect on your eyes, but that may seem a tad seedy :)

    You don't really want to spoil the image on the screen because if you do that, no matter what else you do, you're still getting a degraded image. If the light reaching your eyes from the walls is that bad, I wonder if your image reflectance level is way above standards. I'd hate to think what's happening to your screen image in that case.

    If you combat the problems at the screen, there's a very good chance you will reduce any effects that may be happening at the seating area. The walls need to be dark so light isn't going where it's not wanted (not always possible in a lounge of course).

    Many people like to have everything hidden and only the screen on show - they have black walls floor and ceiling and the speakers are either behind the screen or hidden behind frames (for example), so all that can be seen is the projected image and it gives the impression of floating in space. If you have speakers on the floor near the screen, you will find that the light that bounces off of those can affect the image on the screen (that's measurable too) and be visible (another possible distraction) in your field of view. If you want to be immersed in the movie with no other distractions, a clean screen wall with hidden speakers the way to go IMHO, but isn't always practicable in a lounge.

    If you don't want dark décor in your lounge, a grey screen will work well and improve the ANSI contrast. If it has a little gain, it will further reduce the light that bounces onto your walls. I think in your case Steve, you need to change your screen. An ND filter may help too if reflectance levels are very high.

    Gary
  8. Pecker

    Pecker Well-Known Member

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    I agree, that would be my preference.

    No, and for the very same reasons that I agree with you first point.

    I’m still waiting to see if Me Julie can be persuaded by the 'curtains' pics.

    The silver lining on the cloud is this. You may remember I used to have a cinema room. I should really point out the layout of the house. We have 4 bedrooms - two of them quite large at c.3m x 5m, the other two are half this size - effectively one of those rooms cut in two. One of the bif ones is mine and Julie's, the second large one is Rebecca's (Julie's teenage daughter). The two small ones are Feya & Theo's. Becks used to have the two smaller rooms, and the big one was the cinema room. Then Freya and Theo arrived. Bless 'em.

    Well, becks in nearly 18, and I suspect she'll be leaving home sometime in the next couple of years. The cinema room will be back. :D

    And it'll be dark walls with a fair bit devore at the screen end.

    Steve W
  9. s_inman

    s_inman Active Member

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    Exciting times ahead, just the screen end Steve? If the budget allows why not do the whole room :).
  10. Pecker

    Pecker Well-Known Member

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    Budget will not allow.

    The room will be painted dark (probably dark blue) with black devore round the screen.

    It'll be a CIA screen about 2.8m wide, so just a very small gap between the screen surround and the walls - the devore will go back on the side walls about 1m or so.

    Steve W
  11. gingerone

    gingerone Member

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    Im thinking im going to go with speaker cloth all over the walls and celing with devore above the screen.
    Heres how is so far

    Attached Files:

  12. gingerone

    gingerone Member

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    Got to get black shelves for the alcoves as well
  13. Rich H

    Rich H Member

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    I recently did an "Maximising Image Contrast" upgrade tweak to my room and thought I'd share, via pictures. Perhaps there are some ideas that can be of use to others here.

    (All these were taken quickly with my iPhone camera...heck...do any other cameras even exist any more?....)

    I don't know why I didn't do this sooner. It's one of those obvious solutions that took using my room for a couple years, to come up with. Solution: more curtains! As I've already detailed on this forum before, my room is a living room turned into AVroom/Home theater room/music listening room/reading/hang out/entertain guests room. But I have always sought to somehow maintain very high performance for music and picture in the room.
    Hence a nice welcoming room by day must transform into a theatrical, non-reflective room for movie watching.

    I already have a dark brown felt ceiling build-down, dark carpet, dark sofa, black velvet screen wall around the image, black velvet "stage" area on floor and black velvet covered speakers.

    I kept the 2-tone color scheme by using rich, chocolate brown velvet curtains strategically throughout the room: to each side of the screen, on the side screen walls, on one side of the room entrance, and one in a room corner. I chose brown over black velvet because it just looked much nicer, warmer, more decorative and it blended better. Here's a link to how I was killing reflections with the brown curtain material:

    Rich H's Variable Image Size Home Theater - Build Thread - Completed! - Page 3 - AVS Forum

    But there were still some bright areas of wall left, and I keep searching for perfection. I'd posted image in the previous "maximising conrast" thread, showing how I was experimenting, putting up black material to cover the remaining bits of bright wall to the far sides of the screen. Once I saw that even this increased image quality, I made it a habit...but it was awkward to do - hanging up the material, putting it away, hanging it up....

    I wanted a quick, easy solution that was more permanent.

    My solution is now finished: I added more curtain tracks into the room. Essentially, I added tracks that span the entire side walls, and along the entire back wall behind the viewing sofa. Now there are black velvet curtains that can be pulled entirely along every bit of wall area. And the room aesthetics haven't changed a bit (I didn't want them to): the black velvet curtain simply slide, hidden, behind the nicer looking brown velvet curtains. I love this double-track concept because then you aren't stuck between "looks best" or "rejects light best." You can choose the curtain type/color you like and that you see all day, but for movies the best possible light rejection material comes out, into use.

    I used a combination of Fidelio Black Velvet (the darkest I've seen; it covers my front screen wall/speakers/floor stage). And also a bunch of the super dark, Devore black velvet that is mostly acoustically transparent. I wanted to minimise the effects of adding the new material to the acoustics of the room, and the surround speakers.

    Here is how it came out, via photos:

    The room by day:

    [​IMG]

    Automated black out window shades part way down:

    [​IMG]

    Taking one corner of the screen, here are the visible brown velvet curtains, behind which are hidden the new black velvet curtains:

    [​IMG]

    Close up you can see the new double curtain tracks.

    [​IMG]

    Black curtains pulled out a bit from behind brown curtains:

    [​IMG]

    Black curtains pulled all the way across the entire fireplace wall - I did a cut-out for the side surround speaker:

    [​IMG]

    This is the other side of the room, though the exposure makes the smaller curtain look darker, both are the brown velvet curtains, with the new black velvet hiding behind them. The smaller brown curtain in the corner hides a black velvet curtain that actually spans the entire width of the room behind the viewing sofa, when drawn:

    [​IMG]

    With the black velvet pulled out near the side speaker wall, and begun to pull out on the back sofa wall:

    [​IMG]

    The black curtain behind the sofa, fully drawn, creates a "black-box" seal around the room with the other curtains:

    [​IMG]

    [​IMG]

    Cont'd next post...
    Last edited: May 7, 2012
  14. Rich H

    Rich H Member

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    As seen in this link:

    Rich's Variable Image Size System - AVS Forum

    My projector is hidden behind the viewing sofa by day, and is on an automated lift that lifts it up high for watching movies. Since the new black curtain is drawn in front of the projector, I simply did a small square cut out for the projector beam. One aspect of this I didn't appreciate until I saw it put up, is how more complete, professional and cinematic the room feels with the projector hidden, and only it's beam of light emitting through the black backdrop. Friends commented very enthusiastically about the look of the room in that respect:

    [​IMG]

    This all takes literally seconds! The black velvet curtains are on an easy-sliding track and just whip out pretty quickly across the wall spaces.

    When I feel like completing the effect, I also have a length of black Fidelio velvet I put on the floor in front of the screen, which increases the depth of the velvet covered floor beyond the screen. (When I had this panel of velvet made, I had a small length of metal chain sewn into the seams of one end. That added weight at one end makes it really easy for one person to drop it on the floor, and do a quick tug on the other end to straighten the panel out along the floor...whereas without that weight trying to straighten it on the rug could be more challenging):

    [​IMG]

    Finally, remember I've had to over-expose lots of these shots. The rest of the visible room (rug/sofa) is actually quite dark and non-reflective. So with the lights out it really goes bat-cave:

    [​IMG]

    And you get that image-floating-in-blackness effect:

    [​IMG]

    In these conditions, the contrast of the image is stellar - the intrascene contrast especially is amazing - it's not only more vivid and dynamic - it's consistantly so, because the room has such little effect on image, the sense of deep contrast remains from shot to shot, whether bright, dark, or mixed. There's a more real, solid effect to the image.

    The other huge benefit is the "immersion factor." When the room disappears, the image takes on more of a window-into-the-film-world look, and dimensionality. And with only the image to see, you just get sucked right into the experience.

    So, it took a while to figure it all out, but now I feel I've really got the best of both worlds: A cheery, very inviting room by day or night for hanging out. But a bat-cave-level performance for watching movies, made easy to achieve with minimal hassle.

    I often view movies at other people's houses, including at my friend's place. He just bought my previous JVC RS20 projector from me, so it is intriguing to compare the viewing experience with the same projector, in different rooms. His room is a pretty typical room, not really treated for reflections, with all the equipment (and equipment lights) beneath the screen. It still looks very, very good. But in terms of over all image quality, and especially the "experience," it's really on another level in my room at this time. It's just more real and immersive and intense.

    I've just added a Panamorph UH480 anamorphic lens to my set up, to further increase my 2:35:1 scope image sizes, and wow...just when I didn't think things could get better. :)

    - Rich H
    • Thanks Thanks x 2
    Last edited: May 7, 2012
  15. Rich H

    Rich H Member

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    BTW,

    I have an interesting idea planned for my ceiling that will further make it disappear, that might be of interest, but I'll save that for when it's complete, sometime in the next several months if I get around to it.
  16. gingerone

    gingerone Member

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    Wow Rich that looks awesome. I had intended to do the same with my room but ive opted for fabric instead as a permanent solution.
    Looks really great
  17. bravogolf

    bravogolf Member

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    Stunning. I'd read your frustrations from a while back so it's great to see the final result (which it'll never be, you'll always be playing around with it) and I've read your thread before but it still impresses, especially how finished it is. I love how you can't see the curtain rack
  18. Rich H

    Rich H Member

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    Glad you like it!

    "I love how you can't see the curtain rack "

    Yes, that is a blessing left from the decision to build the ceiling down a bit, in a rectangle. Most people retrofitting and existing room won't go that far, but for people planning a reno, or a new room for HT, I highly recommend this approach. We did a build-down of the ceiling, between 6 - 8" as I recall. It's a rectangle covering the whole screen-to-seating area and we left several inches of space around the whole thing - so there is space between it and the wall. This allows all manner of room additions to be added neatly and discreetly - be it curtain tracks, or more wires, or blinds that are hidden until they drop down, or motors for blinds/curtain tracks...whatever. It's just great to have that hidden space area up there to keep the mechanics out of sight.
  19. Mr_Grinch

    Mr_Grinch Member

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    Thanks Rich H, thanks a lot. Now I have to follow that fantastic build with mine. I was on a real tight budget, hence the parts list and prices. I thought I did fairly well (pics coming when I'm not on a mobile). I'll go from the start of the build, even though it's really only the curtains I was going to post here:

    Parts:

    - Optoma HD200x (£500 - Tesco Ebay outlet. Refurbished, 12 month warranty)
    - Optoma Mount (£60 - Amazon)
    - scruffy piece of MDF (£1 - B&Q Cut offs)
    - cheapo black cotton curtains (£9.95 per panel -Wilkinsons)
    - value curtain rail (£4.95 each - Wilkinsons)
    - 10ft HDMI cable (£7 - Amazon)

    First thing I did was plug in the projector and enter the service menu. 0 hours on everything, turned on/off four times prior to me using it. I'm assuming it was sent back and had to be repackaged, hence sold as refurbished (unless there's a way to reset all of this).

    Next, enlist help of a friend with a drill, mark out ceiling joists (24" apart, darn cheap build houses) and measure up a piece of MDF to mount between the two joists. After that I ran off to B&Q to pick up the MDF and a couple of bolts to attach the mount to. After explaining what I was doing and my budget the B&Q guy had a cut-off almost exactly the right size and gave me two perfectly sized bolts. Top service.

    Back home we go and measure up where the MDF will go and where on the MDF I'm going to attach the mount. Then we drilled two holes straight through the MDF and recessed the underside so the head of the bolt sat flush. A couple of wingnuts later and the projector mount is attached. Huzzah! We then popped the MDF up on to the ceiling joists and attached the projector.

    Surprisingly it was aimed perfectly level, perfectly straight on and projected at exactly the right height. That was lucky.

    I watched a couple of bits and pieces on it that evening and was impressed, but could really notice the light reflection from the walls (again, new build, everything is cream!) so I took to this very thread to look for advice. After considering devore and hanging some sheets on hooks I decided I couldn't really afford devore at present and that the hooks idea would be a pain in the bum every time I wanted to watch a film, so curtains it was. I stuck up some cheap black wilkinsons curtains on rails, switched on the projector and all was well with the world, the picture had improved massively.

    The eventual plan is to run railings all the way around the room so I can hide the black curtains by the window, and to do something with the white ceiling but for now it still looks pretty good. It's amazing how much some cheap curtains can make a difference.

    Pics incoming soon!
  20. Houldey

    Houldey Member

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    Having read all of your great success stories I hope you don't mine me interrupting without one.

    I have a 4m x 4m x 2.5m (H) room with white walls and ceilings that I absolutely can't 'damage' at all (renting). My best idea so far is probably to build a light-weight(ish) wooden cube frame which sits inside the walls/ceiling and then basically cover it in lengths of devore and/or black cotton fabric. Can anyone improve upon this idea or tell me that it absolutely won't work? The only problem I can see is how to build the frame cheaply/easily but such that it can support the weight of all the fabric. Also we're talking £1000 of devore, which is slightly upsetting.

    My physics is not great, but shouldn't a cube frame be very strong considering all the triangles?

    I realise that this probably makes a lot of you cringe, but sometimes needs must and I almost prefer having to do things differently. If I owned a house with a spare room that was born to be a bat-cave and 15 grand to spend on a 4k projector, that would surely be great. But it's just too easy in a way. I like the pain of overcoming non-ideal situations! However I don't like wasted effort/time hence the request for help. :smashin:

    Finally this has probably been asked before, and maybe there should be a sticky, but what are other fabrics like compared to the devore when factoring in price. I.e. if devore costs X times as much as material Y, does it make the HT X times as good, or is it a case of diminishing returns.

    P.S. Someone mentioned in PART 1 that the devore is quite transparent when held up to the light, but this doesn't seem to make sense to me. Something that absorbs the majority of light necessarily has to be close to opaque doesn't it?

    Many thanks and keep your HT stories coming,

    Houldey
  21. gingerone

    gingerone Member

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    Im in the same position with a rented house. Im using drawing pins to hold it all up.
    This means that when i take it all down a lick of paint should fill all the holes without any problems.
    Ive decided to go with black cotton for the back of the room which is only 3.99 for 1m x 2m length and will use devore or something similar above and beside the screen.
  22. Houldey

    Houldey Member

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    Does the drawing pin method work on the ceiling, though? Ideally i'd want a totally non-damaging solution but I spose pins is much less effort. I have inspections every 3 months though so it's not quite as easy as tarting the place up right at the end of the tenancy!
  23. gingerone

    gingerone Member

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    I will let you know. Havent started the ceiling yet.
  24. mcspongy

    mcspongy Member

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    How/where are you mounting the screen? If you're seriously contemplating spending a grand on Devore (which weighs very little btw and light doesn't pass through) you might want to consider spending the money on a screen which maximises your existing room environment instead, so i would have a good read through the projector screens forum.
  25. bravogolf

    bravogolf Member

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    That's true, you could get a grey screen to improve blacks, something like the Stewart Firehawk G3
  26. Houldey

    Houldey Member

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    Yes I see your point. To be honest I had projector a couple of years back. It was the hd700x I think - 720p but not bad at all. I even built a cheap screen using a wooden frame and some blackout cloth. The cloth was certainly not bright white, so it probably helped blacks a bit. But the bright white walls and ceiling killed the image imo even with an otherwise completely light-controlled room. It was not good enough for me to enjoy (I am a bit picky to be fair) so ultimately I returned the PJ. A couple of months back I was having a clear out and decided to chuck the screen! That was a bit silly in hinsight, as I've now got the bug again. I want to do it right this time, though!

    I know someone here has tried it (ke(l)vin something), but I did toy with the idea of creating an enclosure for the screen, with a depth of 1 to 2 metres - a tunnel in mid-air basically, leading toward the screen. The problem with that is that it just looks silly though, and I'm not sure that enough reflections would be blocked.

    Finally, grey screens kind of kill whites, so it's not really a solution imo. It's just shifting the problem from blacks to whites. I suppose a washed out image is certainly worse than a less white image though.

    Anyway I'll have a think about it. I think if I do it I will not use 100% devore, if any. If I do decide to do it I'll make sure to take some photos. It will be the most amateur setup in the world, and the world's biggest/oddest bodge. Might be a good craic though. :thumbsup:

    Cheers,

    H
  27. Houldey

    Houldey Member

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    To be honest 'proper' screens make me cry as they seem so overpriced. Also, if you can't drill into the walls you can't really use a pull-down. The pull-ups are more expensive and a bit big and ugly. I'd love a fixed frame as they are easily dismantled (I presume - poppers), but imo they are a rip-off. There's some serious mark up for some aluminium and a bit of screen material. I think the best saving to be had in HT is with a home-made screen, be it a painted wall or some bit of wood and some cloth. I just pretend to myself that the proper screen material doesn't improve picture much!
  28. bravogolf

    bravogolf Member

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    I've never had a 'proper' screen either so can't comment on how significant (or not) an improve there might be, but am getting a second hand one soon so looking forward to that :) If you read the projector screen forum there are some great DIY screens there, it looks a fairly standard approach has been agreed for making some beautiful screens
  29. Rickyj @ Kalibrate

    Rickyj @ Kalibrate Active Member Assured Advertiser

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    The screens that are designed for ambient lit rooms i.e black diamond,react ii, grey screens etc, do help the situation, but if you have the facility to darkern the room with velvet, this will be the preferred route;)
  30. Rickyj @ Kalibrate

    Rickyj @ Kalibrate Active Member Assured Advertiser

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    Grey screens do not have to kill the whites now if you get the right screen;)

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