Oz Theatre Screens
Technical Info
Screen Ratios & Formats

The two main aspect ratios we watch today are HDTV (16:9) and Cinemascope (21:9). Broadcast TV is displayed in the 16:9 aspect ratio as are many films. Cinemascope films are one third wider again but because TV’s and Projectors are fixed panel devices, black bars are added top and bottom to fill out the shape of the HDTV format and keep the image geometry correct (See the anamorphic options page for image example). This is called ‘letterboxed 16:9' format. With a TV you have no choice but to watch Cinemascope films with an image area smaller than the News with black bars top and bottom. But with projection we can emulate what is done at the cinema by using an anamorphic lens or a zooming projector to expand the image to fill the 21:9 screen. Cinemascope screens are gaining in popularity an are seen as the future-proof projection format.

The other not so popular format is the traditional 4:3 (1.33:1) format. Think 4:3 mode - MASH, Hogans Heroes, old Movies and computer presentations etc. 16:9 HDTV - current TV programming, Sporting events and many Movies. 21:9 Blockbuster Movies -  Lord of the Rings, The Matrix, Oblivion etc.
Screen Sizes And Seating Distances

You will always know your seating distance before knowing your ultimate screen size. There are a few formulas out there that can help, some of them a little vague in getting you the right image size for your seating distance. Generally speaking, the majority of seating distances for home theatre applications are between 3 and 6 metres from your eyes to the screen, with 4-5 metres being the most common.

Using 4.5 metres as a guide in this formula. We divide the seating distance by 3 to get the image height. This would give us a 1.5 metre high image which is close enough to our 120 inch screen (1488mm high x 2646mm wide) Keep in mind using seating distance / 3 is a guide only.

What about 4K? With 4K projectors available now and 4K media not too far away, you may wonder how much more immersive and how much closer you can sit? You should be able to sit as close 1.5x the image height from a 4K display. We have the new Sony 4K projector on display with 4K content so happy to demo this for anyone seriously considering this amazing projector. Our demo room has seats at 3.5 metres from a 165 inch scope screen so we’re essentially .91 times image width from the screen. 1x is probably more ideal for most. No real magic formula here as the resolution is higher than what the human retina can resolve, so it comes down to your own choice and what you think looks good. Of course, you won’t sit 1 metre from such a screen but you can be as close as 3 metres and even closer with smaller screen sizes.

What about rooms with 2 or 3 rows of seats? There's no magic formula here. There will be 1 row that will be the optimum distance from the screen, normally the middle row in most cases, audio quality pending too. Keep that in mind when putting together your room as the distance between recliners is normally around 1.4 to 1.6 metres.

Don't forget what your projector can do either. Some projectors are just not made to light up large screens. Others have ordinary fill factor so screen door can be visible on some more than others. Other projectors have great fill factor and are bright enough to light up large screens, with or without the help of an Anamorphic Lens. If you grew up sitting in the front stalls when visiting the Cinema you may wish to go larger.

Several factors dictate how large your screen can be: Projector brightness - Seating distance - Room length - Projector technology used - What you prefer.

There are other formula's, but it's not rocket science and it's all to easy to get caught up in the numbers. Even with the above formula, you could pull those screen sizes out of hat and land on your feet in most instances. The best advice we can offer is read reviews, test out screen sizes before you buy and talk to us, we design and build cinema screens! It's what we know.

Feel free to call us on 07 3804 1930 for some free advice.

Screen Gain And Material Finishes

Screen gain or 'gain' is a measurement of the screens reflectivity. It has a reference standard by which gain it is measured, that being magnesium oxide (plaster). This is a zero gain diffuse material which measures 1.0, this means it has no gain at all. For Home Theatre applications, we have found a sweet zone for the gain of a material, being 1.1 to 1.3. Any higher than 1.3, the surface can glare or hot spot. See image simulation below to see what this means. Any lower than 1.1 means the image can appear quite dull and lifeless which can be likened to using a wall instead of a decent screen. Reflective screens materials are the most commonly used in home theatre applications.

Back in the day when projectors lacked lumens, high gain screens were all the
rage. Today they are rarely used in home cinema because projectors are now
sufficiently bright enough. We've exagerrated the image on the right to show
you how it can look.

Be wary of the textured fabrics offered on 99% of motorised and most cheap fixed screens on ebay. This is old data screen material is used in Asia because it’s cheap to manufacture. The market here in Australia has been flooded with these cheap imports. You cannot achieve image accuracy with this cheap out dated data screen fabric

Today's Projectors are artifact FREE (Think of the clarity of 2K and 4K Projectors and Blu Ray). Do not introduce artifacts into your image by using cheap textured screen material. The problem with textured materials in today's world of 1080P and beyond is seeing the texture during movies. The above photo shows the textured material on the left side
vs Evo 4K on the right. A simulated image of what you can and will notice on the right, particularly in camera panning moments or times where the image on screen is a light colour, such as sky or snow etc. The image 2nd far right is what you should expect when using a good quality screen surface such as our Evo 4K vinyls.

The idea of the screen disappearing when being used is really what it's all about. You don't want to see the screen material, the frame or have any other distractions. An anomaly and artifact free image is what you should try to achieve.

Our projection materials were designed with this in mind.

Velvet Frames and Over-Scanning

One of the integral parts of what makes an excellent cinema screen is the frame surround, something that’s often overlooked. The blacker the frame, the crisper and neater the image will appear to sit on the screen. When using your projector, you will notice the edges of the image are quite undefined and soft, there will be some noise and grain on the edges, particularly with HDTV sources. Given the fact that you won't want any gap between the image edge and the frame, that soft edge is pushed onto black velvet (the usual amount is 10-30mm). It also helps the screen itself disappear when in use, which is ultimately what you want to achieve.

Other screen manufacturers use what is called ‘economy flocking’, this is a much cheaper dark grey imitation velvet, see image on right side. We only use Black Fidelio velvet on our frames and you truly need to see this to appreciate how black it really is. Call for a sample and we'll happily post some to you. The black Fidelio velvet soaks up over-scan with ease. It is the blackest material on the planet bar none. It is a true velvet with a 1.5-2mm pile. A truly luxurious material, made in the USA by JB Martin. Fidelio velvet is exclusive to Oz Theatre Screens and comes standard on all Majestic screens.

Black Fidelio velvet in broad daylight, it almost looks like trick photography but it's not! It is simply blacker than anything else on the planet. Fidelio again on the far right image and the other materials are flocking’s that some of our local competitors use.. They don't even come close to the black level of Fidelio.

Ambient Light, Room Colours and Paint

Any projection setup will always work best without any ambient light present. As a screen manufacturer, we realise this is not always possible. Many people will use a loungeroom or a combined family room as the Home Theatre and often there will be ambient light problems. Luckily today, many projectors have high lamp mode settings such as 'daytime' and 'vivid' modes. These help deal with some of the ambient light but are not the 'best modes' the projector can display. You should try and get as much light out of the room as possible. Perhaps not so paramount for sporting events and TV, but for those blockbuster movies, night time viewing may take credence over daytime viewing if ambient light is a problem.

Grey screens can help by boosting the contrast level of the projector when using in less than ideal conditions. Dark grey screen materials are less suited for Home Theatre applications because they can crush the colours. Sure they boost black levels and contrast (which are the first things to be diminished by ambient light) but dark grey materials tend to darken all other colours also. Whites become grey, yellows push towards orange etc. So there is always going to some kind of trade-off when trying to get a nice looking image in the presence of ambient light. A lighter grey material is better and why we have developed a light grey Evo Ultra Grey 4K vinyl for use in such conditions.

The ultimate projection room will always be void of ambient light and will have dark coloured walls and ceiling. All projectors used in Home Theatre applications will always work at their optimum when light is removed from the room. Think of your local cinema.. Dark floors, dark walls, dark ceiling, light out when movie starts.

These are the 4 most important factors in a projection screen besides colour temperature of the material.
1. The velvet should be jet black.
2. The material should be smooth and the right gain.
3. The screen should vanish when being used.
4. The material must be non opaque, which means no light should be lost to the back of the material where possible.

The darker your projection room the better the image will appear. Rosco's black velvet paint is said to be the matte black paint of all paints and Solver’s poster black the flattest of flat paints. See below for details on where to buy this. Black however is not the colour of choice for everyone. Many media rooms are dual purpose, lounge room, family rooms etc. Choose dark colours where possible. Visit your local hardware store and ask for some advice. Avoid gloss paints where possible.

If you don’t want to paint the walls, use dark coloured curtains that you can open up when the room is not being used for movies. Curtains are also great for sound too.

For those who wish to order this paint, here are his details. It's $90 for a gallon, which is 3.78 litres.

It is called Supersaturated Roscopaint and the colour is Black Velvet #6003.
Adam P. Smith
Rosco Australia Pty Limited
42 Sawyer Lane, Artarmon NSW 2064
(02) 9906 6262

Another extremely good black paint is made by Solver and is called
'Scenic Flat Acrylic' and the colour is 'Poster black' This is a flat black
paint and will absorb most of the light bounce in your room to the point
of it being a non issue.

Some basic tips on getting the room dark:
>> Block out windows with either 3 pass blockout curtains or side channel blinds - the best idea!
>> Treat the ceiling in a dark colour, even if only the front half. You would be surprised how much of a difference this can make.
>> Treat the screen wall in a dark colour - if you have limited choices as to how dark you can go and maybe want a feature wall,
try and settle on a dark colour - maroon, navy, dark greys, browns etc.
>> If you're screen is close to the side walls, consider making these a dark colour also.
>> Get flat or matte paints where possible.