Screens
There are a number of trade-offs to consider when deciding on the best screen size for your cinema. It is usually considered desirable to have a large screen compared to the size of the room; however, attention must be paid to the principles governing viewing angles.
Usually, this means that the larger the screen, the further away the front row of seats should be from it. 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 allows for “true” ratios to be achieved, on the other, the projection backing plates must 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. 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.
Projection facilities
It is crucial that the architect designing the venue pays attention to this area at an early stage in development. The projection box is pivotal to the functionality of the venue. If a twin or multi screen is planned, the projection facilities should ideally be within one area or linked within the same floor.
The projection box should be wide, high and deep enough to allow for all of the necessary equipment and for the projectionist to move freely around it. Other considerations include floor rigidity and loading, cooling for the Xenon arc lamps fitted to projectors, general air conditioning, storage, good internet connections and rest areas.
If you wish to screen traditional film formats as well as digital, you should also consider:
- The environment that film is stored and used in must be clean and free from dust
- 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 projectors for twin projection (archive prints aren’t supposed to be spliced together) so the box will need to be much wider than that of a commercial cinema.
For all projection, it is essential that the projector’s light beam will clear audience members’ heads, even when they are standing. At the same time, it should not be at too steep an 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 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 it represents an additional cost, it is worth getting cinema sound and projection specialists involved at this stage, as changing an error with any of these elements retrospectively can be extremely expensive.
Ventilation should allow for the ambient temperature of the room to be comfortable for the operator when 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. Consideration should be given to the amount of electrical power required and if single or three phase supplies are needed. Portholes should be fitted so that sound breakthrough from the projection equipment is minimal or non-existent. This can be crucial if the cinema’s seating is close to the projection box equipment.
Film formats
Moving images come on a variety of formats including DCP, video and film. Traditional film gauges include 8mm, 16mm, Super 16mm and 35 mm. When programming archive prints, IMAX or short films, you should ask what format the film is available in.
Digital and video
DCI-compliant digital cinema is presented in the JPEG 2000 file format, with encrypted feature films sent as Digital Cinema Package (DCP) files to the cinema either electronically or on portable hard drive and downloaded or ingested on to a cinema server for screening.
Where films are encrypted, keys (Key Delivery Message or KDM) to unlock them for screening will be sent to the cinema separately by email.
If you are dealing with local filmmakers or screening obscure or archive material, you may come across material in a range of other formats. The most common are pro res digital file and Blu-ray or DVD disc; with more historic tape formats (like HD Cam, Digibeta and BetaSP) very occasionally still screened.
Projection quality depends 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. Blu-ray produces very good quality results and the equipment is good value for money.
Choice of projectors
The minimum standard digital format agreed by Hollywood studios is ‘2K’ – which means that the projected image has a resolution of 2,000 pixels across the width of the image (4K projectors are also available along with hugely powerful 8K projectors for digital screenings of IMAX presentations).
In order to screen films digitally to this professional standard, the minimum equipment required is a 2K digital projector and cinema server.
As above, films are distributed as encrypted DCP (Digital Cinema Package) files, which are usually delivered electronically to cinemas and downloaded on to cinema servers, with some still sent on portable hard drives.
When films DCPs are delivered, the projectionist downloads/ingests them on to the cinema server. Separately, they are emailed a key (KDM – Key Delivery Message) by 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, non-theatrical exhibitors to screen film using digital projectors but in a lower resolution than the agreed theatrical professional standard. Most community cinemas and film societies show film from Blu-ray or DVD discs, made available some months after their theatrical release date, though increasingly non-theatrical distributors like Filmbankmedia supply downloadable digital files (not DCP) for them to screen from.
Blu-ray/DVD players
With contemporary digital cinema systems, it is possible to screen from a variety of disc formats through your digital cinema projector. You should ensure the video players in the projection box can play the relevant formats or that films arrive in a format you can project. If your cinema is showing films from around the world, it’s especially important to check that films comply with local standards. Blu-ray and DVD players are also region specific, thus most UK players 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 offer this. Aside 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 from Blu-ray and DVD so it is always advisable to opt for Blu-ray wherever possible.
Aspect ratios
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 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 occasional exceptions, usually arthouse and independent film, that will have been shot in Academy and or 1.66:1 (aka European Widescreen) ratios 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).
Archive prints
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, 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 competent and experienced at handling them. Replacing reels can be very costly and some prints are irreplaceable. You will need to use single 2,000ft 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 it 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 – with markings rubbed off once the film has been shown.
Silent prints
Silent films were originally made with no soundtrack, meaning that the entire frame was taken up with the image. Some had soundtracks added at a later stage, but if not, a musical accompaniment of some sort will be needed.
Some musicians provide pre-recorded soundtracks to silent films but live soundtracks, although obviously more costly, are always a special experience for audiences.
To screen silent films you will need variable speed control on your projectors. The cinema’s installation engineer or projectionist should be able to advise if this can be done.
Sound
Sound technology has advanced rapidly in recent decades 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, following the advent of digital sound, the quality now attainable is much higher than it was with analogue formats. Almost all new releases have six channels of digital audio information, included on a digital bit stream in the DCP files and fed through a digital sound processor.
It is best to seek professional 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 possible sound quality, cinemas need a multi-channel system, with sound fed into speakers at the left, centre and right behind the screen, and to an array of speakers around the auditorium, to create full ‘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 stay in sync with the sound. Where this is the case, an interface must be brought in 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 screen 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.