There are a number of “trade offs” when selecting the size of the screen for a venue. It is usually considered desirable to have a large screen compared to the size of the room. Attention must be paid however to the principles governing viewing angles. Usually this would mean that the larger the screen, the further away the front row of seats would have to be from the screen. The ideal picture size is that which subtends a horizontal angle of 45 degrees at the prime seat. The prime seat is two thirds of the way back on the centre line of the theatre. Most cinemas make provision for showing Cinemascope (1:2.35) and Widescreen (1:1:85) ratios. It is usual practice that the majority of cinemas will use fixed top and bottom, and variable side masking, to allow for a clean cut image. To ensure that true ratios are achieved, especially when more than the two standard ratios are required, variable top and side masking should be used. Some venues project the image onto the screen without using masking. On the one hand this will allow for “true” ratios to be achieved, on the other, the projection backing plates would have to be cut by someone with expert precision to achieve sharp edges to the picture.
There are a large number of types of screen material available and the type used would depend on the venue. They range from highly reflective, to matt white, to silver for 3D projection. Cinema loudspeakers are usually placed behind the screen; therefore most screens are perforated to allow sound penetration. For small venues with seats close to the screen micro perforated material is available.
It is important that the architect designing the venue pays attention to this area at an early stage in the development. The projection box is pivotal to the functionality of the venue. If a twin or multi screen is planned it is desirable that projection areas are within one area or linked within the same floor. It is important that the projection box is wide, high and deep enough to allow for all of the equipment. There must also be room for the operator to move freely around the equipment. Other considerations include floor rigidity and loading, cooling for the Xenon arc lamps that are fitted to projectors, general air conditioning, storage, good internet connections and rest areas.
If you intend to still use traditional film formats as well as digital, the following should be taken into consideration:
- The environment that film is stored and used in must be clean and free from any dust particles.
- Films should be stored vertically and you will need lots of room.
- You will need space for film make up and rewind.
- Ceilings should be high enough to accommodate film transport carriers and large spool boxes for 35mm film.
- When screening 16mm film you may require two rather than one projector for twin projection (archive prints aren’t supposed to be spliced together), so the box needs to be much wider than that of a commercial cinema.
For all projection it is essential that the light beam from the projector will clear the audience heads even when they are standing. At the same time it should not be at too steep angle otherwise keystone distortion (i.e. the picture assumes a trapezoid shape) becomes a problem. If the location of your projection box is already fixed, you can alter the angle of projection by changing the position of the screen either up and down or backwards and forwards. It is also important to appreciate that film and most video projectors should be projected from the centre line of the screen. It is not usually possible for all of the equipment to achieve this centreline projection and there is a degree of tolerance with both film and most video projection. Within the projection room there are legal requirements concerning the amount of space between projectors. These rules should be made available to the architect. It is essential that a decision be made at a very early stage as to how many projectors will be installed and the projection room designed around this requirement. Sometimes, although an additional cost, it is worth getting cinema sound and projection specialists involved at this stage. Changing an error with any of these elements retrospectively can be extremely costly.
The ventilation should allow for the ambient temperature of the room to be comfortable for the operator when the equipment is in use. Extraction must also be provided for the projectors. Manufacturers recommendations as to the cubic feet per minute (CFM) of air extraction should be made available to the architect and the heating and ventilation consultant at an early stage. Thought should be given to the amount of electrical power required and if single or three phase supplies are needed. Portholes need to be fitted so that sound breakthrough from the projection equipment is minimal or non-existent. This can be crucial if the cinema seating is close to the projection box equipment.
Most projectors used in commercial cinemas are only able to screen Widescreen and Cinemascope. To screen other ratios you would need new aperture plates and new lenses that would need to be tailored to the auditorium’s specification (projection throw, screen size etc.). Film ratios are a minefield because there are many different rules. The following only skims the surface of this area but does highlight some of the pitfalls and issues that need to be considered.
Prior to 1953, the most widely used ratio was Academy (1.33:1). The most common ratios in use today are Widescreen 1.85:1 and Cinemascope 2.35:1. However, there are exceptions such as the Dogme films and some independent American films that will have been shot in Academy and some European work that will have been shot on 1.66:1 (aka European Widescreen) that may need different lenses and new aperture plates cut. Silent films will either be full frame (i.e. no soundtrack on the print, only image) with a ratio of 1.38:1 or Academy (where a soundtrack has been added to the print) with a ratio of 1.33:1. To achieve a full range of ‘true’ ratios the screen will need variable side and top masking (see above).
Moving images come on a variety of formats including digital, video and film. Traditional film gauges include 8mm, 16mm, Super 16mm and 35 mm. When programming archive prints, IMAX or short films ask what format the film is available in.
Many archive films are now being digitised and reissued but there are still many original archive prints that haven’t yet been changed to a digital format. These require projection on non-digital projectors and often as is the case with archive prints, two projectors. You should discuss with the supplying archive what their presentation requirements are, for example do they allow the splicing together of prints or the creation of cue dots? If they don’t allow the splicing together of prints then you will need two projectors to run reels one after the other on twin projectors.
When screening archive prints exhibitors must be confident that the projectionists are experienced and competent at handling these prints. Replacing reels can cost £300 or more and some prints are irreplaceable. You will need to use single 2000ft spools for screening archive prints because these reels of film cannot be joined together. This means you will need two projectors. Archive prints may be on gauges other than 35mm.
Procedures must be set up to ensure that all archive prints are handled with the best possible care. The most important rules are:
- Print condition reports must be written on make-up of the film and after the film is screened
- Prints must not be put on the floor or any other dusty/dirty areas – racks must be put up if they are not already ‘in situ’
- Prints must be marked up with china graph pencils – this must be rubbed off once the film has been shown
Silent films were originally made with no soundtrack that means the entire frame was taken up with the image. Some have had soundtracks added at a later stage but if the film has no soundtrack a musical accompaniment of some sort, usually a piano will be needed. Some musicians are starting to provide pre-recorded soundtracks to silent films but a live soundtrack, although obviously more costly, is always a special experience for audiences.
To screen silent films you will need variable speed control on your projectors and the cinema’s installation engineer or projectionist should be able to advise as to whether this can be done.
It is likely that most of your material for presentation will be in a digital format. DCI-compliant digital cinema is presented in the JPEG 2000 file format, with encrypted feature film files delivered to the cinema on a portable hard drive (Digital Cinema Package or DCP), and, separately, keys (Key Delivery Message or KDM) to unlock the encryption sent to the cinema by email.
If you are dealing with local film makers or screening obscure and archive material, you are likely to come across material in a range of other tape and disc formats. The most common are DVD and Blu-ray disc formats; and the tape formats HD Cam, Digibeta and BetaSP for industrial/professional uses.
The quality of a video projection will depend entirely on the quality of the production format and duplication. No matter how good your projection facilities are they cannot make poor material look good. It is quite possible to get good results from a VHS tape if the material was originated on film, digital or BetaSP. Blu-ray produces very good quality results and the equipment is good value for money.
Choice of projectors
As digital image technologies advanced through the 1990s, to a point when the quality of a 35mm projected image could be approximated in digital form, the film industry began to recognise the economic and logistical advantages of replacing 35mm with a digital format as the main tool for distributing and projecting films.
As soon as the industry agreed to a standardised minimum digital format for professional cinema presentation, distributors began to offer films, and cinemas began installing projectors to show digitised films. This was initially referred to as D-Cinema.
The minimum standard digital format agreed by the Hollywood studios is referred to as ‘2K’ – which means that the projected image has a resolution of 2000 pixels across the width of the image. 4K projectors are available along with hugely powerful 8K projectors for digital screenings of IMAX presentations.
Copies of the film are distributed as encrypted files, which are then loaded onto portable computer drives for circulation to cinemas.
In order to screen films digitally to this professional standard, the minimum that cinemas require a 2K digital projector and cinema server. When films arrive in the form of a portable drive (DCP – Digital Cinema Package), the projectionist will load the file onto its cinema server. Separately, the projectionist will receive a key (KDM – Key Delivery Message) from the distributor, which enables the projection of the film from the server, for an agreed period of time.
When looking to acquire digital cinema equipment, considerations regarding location, space around the projector and ventilation in the projection box apply.
Digital advances in the market and in technology have enabled other exhibitors to screen film using digital projectors but in a lower resolution than the agreed professional standard. Many community cinemas and film societies have been started using DVD or Blu-ray as the source material, and screening films some months after their national release date once the DVD is released. Some community cinemas have also installed digital projectors or use ‘touring’ digital projectors.
With contemporary digital cinema systems, it is possible to screen from a variety of disc and tape formats through your digital cinema projector. You will need to ensure that the video players in the projection box can play the relevant formats or that films arrive in a format you can project. If the venue is showing films from around the world it is especially important to check that films comply with local standards. DVD and Blu-ray players are also region specific, thus most players in the UK will only play region two and B.
It is possible to purchase “Chipped” DVD players that can access all regions (there are six in total), and there are many electrical stores that will do this. Apart from playing commercially made DVDs, the player should also be able to play DVD-R format where a disc has been authored on an individual basis.
Films on Blu-ray are increasingly being issued in region-free formats and can be played on most Blu-ray players around the world. However some distributors do still impose region specific content. There are three regions – A, B and C. A is USA, B is Europe and C is everywhere else.
There is a marked difference in quality between screening a DVD and Blu-ray in a community and any other cinema setting, so it is always advisable to opt for screening from Blu-ray wherever possible.
Sound technology has advanced rapidly over the last decade and the sound levels now attainable are very high. Because of this, building-born sound needs to be taken into account and auditoria need to be isolated effectively from the outside environment to prevent sound leakage.
Similarly, with the advent of digital sound formats in the early 1990s, the quality now attainable is much higher than it was with the older analogue formats developed in the 1970s.
Almost all new releases have six channels of digital audio information. These used to be squeezed onto the outer edge of the 35mm film but now everything is on a digital bit stream delivered to the cinema via satellite, high-speed internet connection or hard drive with the film, and fed through a digital sound processor. It is best to seek advice as to what type of sound processor will suit the needs of your cinema. For example, certain processors may be more suited to Event Cinema than others. To attain the highest sound quality a venue needs to have a multi-channel system. The sound is fed into speakers at the left, centre and right behind the screen and to an array of speakers around the auditorium to create ‘surround sound’.
Dolby Digital is the standard format now although other suppliers (notably DTS) have produced systems with even more channels (producing an even cleaner sound) that are supplied separately on digital disks and require additional playback equipment.
If using video you will need to ensure that the venue’s sound processor is able to accommodate it. Some video projectors are unable to keep in synchronization with the sound. If this is the case an interface has to be hired or bought to achieve sync. For stereo, one interface unit is required, and for multi-channel sound three units are required. The projection supplier should be able to advise on this.
Summary of key points from Chapter 8
- Seek professional advice from an independent specialist adviser at the earliest opportunity
- Think carefully about the siting and design of projection boxes. You need to take into account ergonomics and legal requirements
- When planning your equipment purchases, don’t forget that you may want to use formats other than digital
- Archives may have stringent presentation requirements
- Sound quality is as critical to audience enjoyment as picture quality but is often overlooked. Use an acoustic consultant if you are unsure.