Technical Information
Proudly Australian made. Oz Theatre Screens has a fanstastic reputation in the screen industry not only because of our great level of customer service but more importantly the visual and build quality of our screens is second to none. We have extensively researched all facets of projection screens for many years and continue to pour countless hours of R&D into our products to ensure you are enjoying the best of the best when it comes to getting the most out of your projector. Not only does Oz Theatre make the best frame, have the blackest velour, the longest warranty and the best prices, but we also have the best projection vinyls available. Sure, you can use a white wall, you can also fit a Porsche 911 with cheap re treads, it will drive and get you where you need to go but you will never see it's full handling potential. The same goes for projectors coupled with a cheap screen, the end result is inferior image reproduction.
Invest in the best and buy a quality Australian made product. It will last you decades. Another important thing to note is when you buy an Oz Theatre Screen you don't have to settle for limited stock sizes, we can custom make your screen down to the millimetre. 'Another Shade of Grey'Regardless of the ‘shade of grey’ You simply cannot get an accurate image. Sure grey will boost the black level on screen, but so what? Digital projectors have excellent black levels these days. Companies selling grey screens are clinging to the old idea that digital projectors cannot produce good black levels. This is nothing more than mis information.
Fact: Any projector will look it’s best in a light controlled room. When you go to the cinema is there light in the room?
Are the screens at your local cinema grey? The answer to both questions is no.
The same goes for the home cinema. Controlling the light is one of the most important things to consider. If you cannot control the light to some degree then a projector is not for you.
1080P ready, 1080P certified? What is going on? Hasn't this saying been used and abused of late! Now everyone has 1080P fabric and 1080P certified screens. The truth is there is no such thing as a 1080P certified screen fabric or a 1080P certified screen. It's something that scrupulous sellers (especially on ebay) have decided to mislead us with. Nothing could be further from the truth. 1080P is a very fine resolution, over 2 million pixels per panel. What one should try to achieve is 'accurate pixel placement' on your screen surface. Sadly this cannot be achieved on these run of the mill motorised and pull down screens. 99.95% of motor and pull down screens use a woven backed fabric with a white impregnated front surface, this creates a rough surface, like rendered concrete. This creates image noise and is the opposite of what you should be looking for. Oz Theatre Screens is the only company in Australia (there is a couple in Europe) that would actually qualify for a 1080P projection vinyl. Evolution3D is the smoothest fabric in the world. This allows for the most accurate pixel placement and the sharpest possible image (focus) from your projector. Think of a white IKEA bookshelf vs a rendered concrete wall. The idea of the screen vanishing when in use is what one should be trying to achieve.Recently there has been quite a bit of confusion surrounding the terminology on the apparent brightness of projection screen vinyls. Please read on to learn where the term 'brighter' should be used. Brightness is being confused with lighter - an image that appears less saturated and often washed out or lacking in accuracy. Please see these image examples below.
How important is contrast? Contrast is also key to a good image. High contrast is difference between the whitest whites and the blackest black on screen. The more shades in between white and black, the better the image, the better the colours and the better the shadow detail. That is exactly why the cinema is dark, to keep the blacks black. Any ambient light will wash out the image and ruin any contrast. Some companies promote grey screens for home cinema. The year is 2009, the contrast ratios of projectors in this day and age is more than sufficient. We do not need grey screens at all. If you are planning on using a projector in an environment where ambient light is an problem, dont go grey. The bad far outweighs the good. How important are black borders and surrounds on your viewing surface? A nice jet black velour surround is the ultimate finish to any fixed projection screen. The advantage of fixed screens is you can have a rich, jet black velour frame that yields a brighter, crisper and more colour saturated image. The blacker the borders the more intense the picture is going to appear. See below for contrast illusions. The main advantage of a Black Velour frames is not to soak up overscan but to enhance the image. Have a look below at a comparison between a powder coated frame and a velour frame. No matter how accurate you project the image onto the screen, with a powder coat frame there will always be annoying reflections coming off the frame. Using jet black velour assures zero reflections and a beautifully masked image. Using a velour frame not only adds a touch of class to your screen it also ensures that the projected image appears how it was meant to be with no distractions. At night time your screen should dissapear when it's being used.
Fig 1.
Fig 1 Note the grey boxes on the left side of figure 1 appear to be lighter than those on the right hand side. Now roll your mouse over the image, you may be surprised to see the grey boxes are indeed all the same colour. This is a prime example of how much brighter your picture will appear with a black velour frame surround. It may an illusion but it works well. We do not recommend coloured frames, especially timber style frames with fancy edging. If the frame does not have black velour masking on the inner edge consider it a badly flawed design. Always insist on a black velour frame finish.Sharper edges for your image Not such a massive problem with blu ray and hd dvds but for standard definition dvds you will find the edges of the image very soft and blurry. This is another reason black velour is used. The idea here is to actually overscan the image approx 3mm on all 4 sides to take away the soft edge of the image. The difference is simply astounding. Our black velour is quite the light sponge, you will never notice over scanned image on our velour simply because it's just so black. Overscanning used to seen as the lazy way to get the image up and running but in reality it has real purpose. See the cropped images below. The top image (scope film) has no velour on it's bottom edge, you can see the grey bars being projected onto the screen and you can see the soft edge. The image under this has a nice crisp and sharp edge because the slightest amount of over scanning was done to remove the blurred edge. These are real screen shots but we have needed to, in this instance, add the black edge in on the bottom image as this is just not possible to capture on a computer monitor. If you live within driving distance please feel free to arrange a private viewing, we can show you this in person.
Here are two real time screen shots of our black velour VS a matte black painted wall. We shifted the lens off the left side of the screen and took two shots with the DVD on pause. The left shot is without the flash, the right shot with a flash, we then turned up the brightness on the right hand shot so you can see the difference. This of course is not required if you see this in person, the matte black painted wall clearly shows the image without the flash. Our black velour is the best light absorbing velour on the market, hands down. This product is something very unique to Oz Theatre Screens.
"A screen surface has a gain of 2.4 and a 180 degree viewing angle". This is scientifically impossible. You cannot cheat the physics. The apparent brightness of a high gain screen simply must drop off when you get further away from the centre. It cannot reflect back more light than is being projected onto it. Even the best reflective surfaces absorb a small percentage of the light that falls onto the surface. Today there is a very strong movement away from high gain screens. Which, in fact were first developed for low powered projectors - 400 ANSI lumens or less. Todays projectors are in excess of 1000 Lumens. So high gain screens are just not necessary in home theatre.It is all about how the light is diffused and reflected. A screen surface cannot reflect back more than 100% of the light hitting it. It cannot create light. All a high gain screen can do is directionally reflect the light back in a certain direction, however, high gain screens are either retro reflective, which reflects the light back to the light source (the projector) or reflective which reflects the light back in the opposite direction in the same way that a mirror reflects light. This is how the best reflective projection vinyls work including Evolution3D.There is no possible way for a screen to have a gain of over 1.2 and have a 180 viewing angle with the brightness staying even the further you move away from the centre of the screen. There are screen fabrics out there today claiming to have a gain of 1.6 and 160 degree viewing angle, with 'special' optical coatings making the screen 60% brighter. You just cannot achieve this. They may have a 160 degree viewing angle but the image will look something like the image on the right hand side below.Most importantly is the need for OPAQUE fabrics. This means a fabric that prevents light from travelling through the screen. If you look around you will see screens that use wafer thin single layer pvc substrates. The projected light travels right through these fabrics ruining the PQ and reducing your image brightness and contrast from anywhere upto 40%. Always ask if the fabric is opaque and has a backing to prevent light penetration. And if it doesn't, avoid it at all costs. All of Oz Theatre Screens fabrics are opaque.Have a good look at these image changes below (2nd photo on right). You can see why high gain fabrics are not suitable for home theatre. This is what can happen during a movie when using a high gain screen (including glass beaded screens).
Be very wary of the textured fabrics being offered on 99% of motorised and pull down screens. This is old data screen material is rampant in Asia because it's cheap to manufacture. The market here in Australia has been flooded with these cheap imports. You simply cannot acheive image accuracy with this cheap outdated data screen fabric. In fact it's so bad you would be better off using a white wall! See these photos below to learn why.
Here is another textured fabric that should be avoided where possible.
Ok for data projectors, but this is not for 720 and 1080P projectors.
Here we have a correct image from our premium fabric Evolution3D. The image is reflected back to the viewer exactly how the projector manufacturer intended. No hot spots, no texture, nothing but a clean and accurate image with strict white field uniformity and accurate spectral response.
So always insist on a sample of the fabric, even an A4 size swatch will give you a great idea of how it's going to perform. Remember, the screen fabric is the thing you will spend most of your time looking at.
What is GAIN?
When shopping around for a home theatre screen you will hear the terms "high gain" and "low gain" Gain is the measuremnt of light that is reflected off the screen surface. It's referece to which all screen fabrics are measured against is magnesium oxide (plaster) which has a gain of 1.0 and is a diffuse surface. In other words, a gain of 1.0 means there is no gain at all as it will diffuse light only and does not have any reflective properties. So if a screen vinyl has a gain of 1.2 means this means the screen reflects 20% more light (back to the viewer) than a standard pure white magnesium oxide board under the same conditions.There are only three ways that screen material can reflect light.RETRO REFLECTIVE - reflects the projected light back to the source (avoid)
DIFFUSIVE - reflects the projected light with almost complete diffusion. This means when the light hits the screen it diffuses the light equally all over the screen, resulting in the widest viewing angles of 180 degrees. So in reality it doesn't really 'reflect' light, it diffuses it.REFLECTIVE - reflects the projected light in the opposite direction to the source. If the projector is floor mounted the light is reflected back toward the ceiling, (not where most people sit, right ?)However if your projector is ceiling mounted this is, by far, the best type of surface providing the gain is not over 1.3. Anything over 1.3 will have a tendancy to hot spot. 1.2 to 1.3 is the 'sweet spot' for home theatre.Results and recommendations
White: This is the preferred surface for the home theatre, use only a matte white fabric with a gain between 1.1 and 1.3. A 1.1 to 1.3 gain fabric will give you a universal viewing angle and more accurate color rendition. What to avoid When shopping around for a screen for home theatre, be sure to avoid any screen with a gain greater than 1.4 unless it is used for REAR projection only, (rear projection screens are non opaque so the light cannot hot spot) High gain screens also tend to have beaded or textured surfaces which can be easily damaged, making cleaning a nightmare.
A good quality screen fabric should: 1. Produce true and accurate colors 2. Allow the projector to display it's full resolution with no screen textures visible 3. Give the widest viewing angles - both horizontal and vertical 4. A screen that does NOT hot spot In other words, a good projection fabric should allow you to see the limits of the projectors ability. Evolution3D on the right hand side VS a standard single layer pvc substrate. The difference is astounding when compared side by side. Evolution3D is Australia's first projection vinyl designed specifically for the new crop of 1080P Projectors. Designed with an optically enhanced 1.26 gain front surface that is dead smooth, the fabric itself dissapears allowing both 720 and 1080P projectors to shine with vivid colour and accurate image fidelity. Any 720 or 1080P Projector will greatly benefit from Evolution3D - Oz Theatre Screen's premium fabric. We do NOT use rigid board as a screen surface. Rigid screens can, over time cause the frame to skew out of shape. They also cost a fortune to ship and a hassle to move as you cannot take them apart. Vinyl has been used for over 50 years for fixed projection screens, it enables optics to be mixed into the cast when the product starts off in it's liquid form.
Rigid screen use coatings which deteriorate over time which of course deteriorates your image! Their optical coatings can also rub off which makes cleaning a nightmare. Think about it this way. A good optically cast vinyl has it's optics IN the actual product whereas coated surfaces have their optics sitting on top which leaves the product vulnerable to the deterioration mentioned above. NOTE: Some vinyls are also optically coated. Evolution3D is optically cast - Highly recommended!
The 5 main types of projection fabric we offer are;
Evolution 3D - matte white - fully backed - Thickness 380 microns - gain 1.25 - front projection - spool 2.1 metres
Diamond - matte white - fully backed - Thickness 220 microns - gain 1.1 - front projection - spool 2.1 metres
Greyview - greyscale correct - fully backed - Thickness 320 microns - gain 0.9 - front projection - spool 1.5 metres
Optema - grey tint -rear projection - Thickness 220 microns - gain 1.4 - rear projection - spool 2.4 metres
Acoustic Vision - NEW Moir'e free acoustically transparent fabric - Thickness 400 microns - gain 1.16 - front projection - spool 2.44 metresSee our FABRICS page.
The are a number of reasons that Matte white low gain screens are the best materials to use in a 'Home Theatre' environment.The main advantages of using a 1.1 to 1.4 gain matte white screen surface Low gain screens give a universal viewing angle - this means that no matter where you sit the picture will be equally bright & clear, giving you more seats in your home theatre. Low Gain screens don't hot spot because the light is diffused evenly from edge to edge. High gain screens tend to hotspot because the they cannot diffuse the light evenly. High gain screens are too bright in the centre of the screen and the light reflection falls off quite dramatically as you go further away from the centre Low Gain screens are matte white, this gives a colour neutral reproduction, so all of your movies look natural and life like. Where as high gain screens can have a number of problems when used in home theatre. You can have color shifts in both the blue and red spectrum (hue). Your viewing angles are heavily restricted and high gain screens also hotspot. See the above images of image changes using both high gain and low gain screens.
SCREEN SIZE
The size of the screen is best found by dividing the room's length by 4.5. The actual number you use can be anything between 3.68 and 5.18 and where 4.5 is somewhere in the middle of that. Dividing the room's length by the chosen number gives you an ideal screen height for that room that allows you to work out both Seating Distances and Throw Ratio.EG 1: Room length of 6000mm / 4.5 = Screen height of 1330mm (135 inch 2.37:1 screen)
If you want a larger screen than the math allows, then the best way to test this is to set the projector up at the back of the room and measure the height of the light at the minimum zoom
[smallest image size]. This is handy for also checking the image height when an AT screen is to be used as these usually require the screen to be built out from
the wall.ASPECT RATIO
The aspect ratio is simply the width in relation to the height to denote the shape of the screen. 35mm film CinemaScope has an Aspect Ratio of 2.39:1 meaning the projected image is 2.39 times wide as it is high. As it turns out, our Home Theatre equivalent is 2.37:1. This is because TV's evolution to wide screen has been based on 1.33x steps where SD is 1.33, HD is 1.78:1 [1.33 x 1.33] and Scope is 1.78 x 1.33. The actual math requires the decimal point to be taken to at least 7 places .
1.3333333 x 1.3333333 = 1.7777777 and 1.7777777 x 1.3333333 = 2.3703702.
EG 2: Screen Height of 1200mm x Aspect Ratio of 2.37 = Scope Screen Width of 2844mm
SEATING DISTANCES
With 1080 projectors, you can sit as close as 2x the image height but should not sit further back than 4x. These are based on SMPTE recommendations and SMPTE's preferred distance is 3x the image height and the THX 36 degree rule is 3.68x the image height.
EG 3:
Screen Height of 1330mm x 2.00 = 2660mm [closest seating distance]
Screen Height of 1330mm x 3.00 = 3990mm [SMPTE Preferred]
Screen Height of 1330mm x 3.68 = 4890mm [THX furthest seating distance]Note that in the 6000mm deep room, this means that you are off the back wall, so allowing for Back Surround speakers to be placed behind the seating location[s].
THROW RATIOS
The easiest way to find the Throw Ratio and or Projector Mounting distance is to use the following math.
Scope Screen Width x 0.75 x TR [in this case 2.2 = distance of projectors lens from screen.
OR 16:9 screen width X TR = Mounting distance.
Just for fun, here's some information on 'why a projector and screen is the best value choice'. Plasma TV vs Projector and screen. It takes 6.2 X 42 inch plasma TV panels to fill a 100 inch 16:9 projection screen. See photo below. (to scale)
Sure, Plasma and LCD television is fantastic! It has it's place, in your loungeroom. Not your home cinema room. Home Cinema is a big screen and a projector.
We offer many different size screens and formats for both front and rear projection. 16:9 HDTV and Cinemascope are the 2 most popular choices because HDTV is in 16:9 and movies transferred to DVD are usually in Cinemascope format. See our Cinemascope page for more info. By using an Aussiemorphic lens and a Majestic Scope screen you can now enjoy Deluxe Widescreen in your own home with no black bars top and bottom - The way the Director intended.
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Some common questions answered below:
Lights on or lights off? For the best cinematic experience you should always have your lighting controlled as much as possible. You won't be watching the next block buster at the movies with the lights on, and for good reason too. For years we have all gone to the cinemas and watched movies in a darkened environment. It is done this way because it simply creates a better impact and of course, better contrast. The darker the room, the better and brighter the picture will be, whether it's your local cinema or your home theatre room. It should only be you andAvoid watching movies with lights on, even with new dark screen technology out there, the impact is nowhere near the same. Movies were not meant to be viewed in broad daylight. It might be ok for the wife to watch a daytime soapy, or for advertising in shopping malls. But what was your home cinema really built for? And who watches movies with all the lights on anyway?Don't be put off by a darkened projection room, once you go down this avenue you will never watch movies any other way!We have patented an ingenious method of attaching the fabric to the frame called SCREEN GRIP. This patented method uses a T shaped rigid PVC strip that is inserted into it's corresponding channel in the frame with as little effort as using a soft hammer. Fabric does not get damaged and is easy enough to remove should the need arise. Not only does the SCREEN GRIP tensioning system give you the flattest screen on the market, it also eliminates tradional screen sag entirely. With SCREEN GRIP you will acheive a much smoother and a tighter tension which results in a much flatter screen.Kit form is better! Here's why. It has been the industry standard for a long long time. Kit form or 'knock down' screens come securely packaged in a long narrow box. The Majestic Screen comes with a full color instruction CD, hanging brackets with screws, SCREEN GRIP strips, corner angles and gloves. Everything is supplied to you can get your screen up on the wall in as little as 30 minutes - 2 people recommended.So why not send them out assembled? The main problem with sending screens out assembled are: 1. Couriers do not usually respect the goods they are transporting, therefore the screen fabric and or frame can be easily stressed or damaged. 2. The price - The average 100 inch 16:9 screen in kit form costs $40 to $55 to ship Australia wide. Assembled it would cost between $210 and $390 Australia wide. So think about this, if you can save over $200 on freight wouldn't you rather spend 30 minutes assembling your screen?What format screen? Generally speaking, the vast majority of home theatre enthusiasts are now using Cinemascope format, because most dvds are in this format. There are very few dvds in the 4:3 TV format. So most will optimise their screen for movies rather than TV. Commercial venues such as pubs and clubs generally go with the 4:3 and 16:9 format since they display sporting and music events straight from TV.
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