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Cinemas design involves creating an environment that is tailored to the movie-going experience. This includes considerations such as acoustics, lighting, seating arrangement, aesthetics, accessibility, and technology.
- Types of film and method of projection Four standard types of film are described by their width: 8 mm, 16 mm, 35 mm and 70 mm.
- Each has its appropriate type of employment, screen size and auditorium conditions.
These types of film are described in Table below.
1) Methods of projection
There are three methods of film projection:
- Direct projection from the rear of the auditorium onto the screen. The most common method by far.
- Indirect projection, where the film projection requires one or more mirrors.
- This method is used where lack of space or structural difficulties make direct projection difficult to achieve.
- Mirror projection requires a powerful light source and the screen cannot be wider than 9 m.
- Rear projection. Not possible with curved screen, but may be applicable for the smaller auditorium.
- For this method the picture needs to be reversed, for which mirrors are an economic solution.
2) Cinema auditorium design
Functional requirements include
- Every member of the audience requires an unobstructed view of the whole picture area on the screen, without visual and physical discomfort and picture distortion
- Picture sharpness and luminance need to be uniform and satisfactory, and
- An auditorium giving distortion-free sound reproduction.
3) Viewing conditions
- Film widths of 16mm, 35mm and 70mm.
- The centre of the projected beam should not deviate more than 5° horizontally or vertically from the centre of the screen, or it should be deflected via a deflection mirror. As shown in the figure below.
- Projection screen: Minimum distance of projection screen from wall in the case of THX is 120cm, according to theatre size and system reducible to 50cm with respect to the sound system configuration.
- The projection screen is perforated (sound-permeable).
- Movable blinds or curtains limit the projection screen to the side for the same picture height.
- Large projection screens are curved with a radius centred on the last row of seats.
- The lower edge of the projection screen should be at least 1.20m above the floor. As shown in figure above.
- Viewing criteria are shown in plan and section.
Projection criteria for various formats:
(a) 16 mm film. (b) 35 mm film. (c) 70 mm film
(a) 16 mm and 35 mm film. (b) 70 mm film
- The size and shape of the screen must be related to the shape and rake of the auditorium floor.
- Seating rake is less critical than for concert halls and theatres as the screen can be elevated and sound comes from overhead speakers.
- Nevertheless, a rake of 5° (or less) is recommended. Seating can be well upholstered with a tradition in new commercial cinemas towards comfort, including pullman seats.
- Short row lengths tend to encourage auditorium roving sales of popcorn, ice-cream and confectionery.
- The auditorium should have no outside light other than emergency lighting.
- Walls and ceiling are made from nonreflective materials and in not too bright colours.
- Spectators should sit within the outside edge of the screen.
- The viewing angle from the first row of seats to the centre of the picture should not exceed 30°.
- The floor gradient is achieved by an inclination of up to 10% or by the use of steps with a maximum step height of 16 cm and with aisle widths of 1.20m.
4) Acoustics for films
- The sound track is an integral part of the audience experience and the quality of sound reproduction has vastly improved.
- Cinemas are now equipped with stereophonic sound systems which require acoustically dead auditoria; the ideal is a zero reverberation time.
- Hence all finishes – floor, walls, ceiling and seats – need to be sound absorbent.
- Side walls should not be parallel, and a fan shape is preferred.
- The auditorium should be structurally and enclosurewise insulated from external noise.
- A suitable ambient noise standard for cinemas is NR30 to NR35.
- The volume per occupant should be at least 1.25 m3 for large cinemas and 5 m3 per person for small auditoria.
- Picture sizes depend on the distance of the projector from the screen; height/side ratio is 1:2.34 (Cinemascope) or 1:1.66 (wide screen) for smaller room widths.
- The angle from the middle of the last row of seats to the outer edge of the picture should be at most 38° for Cinemascope.
- The ratio of the spacing of the last row of seats to the projection screen should be 3:2
- 8 mm and 16 mm film is projected with a screen ratio of 1:1.375 and 1:3.135 respectively.
- With 35 mm the screen ratio is also 1:3.375 but may vary between 1:1.65 and 1:1.85: the international standard is 1:1.75.
- The ratio of 70 mm film is 1:2.2.
- Foreign language films call for 1:1.65 to allow for sub-titles.
- Screen size is dependent on light source, screen luminance picture quality, method of projection, viewing conditions and seating capacity.
- The maximum widths of 0.9 m for 8 mm film, 4 m for 16 mm and 6 m for 35 mm are accepted.
- For uniform focus a large screen should be curved to keep its surface equidistant from the centre of the lens.
- Size is simply the relationship of the area occupied by one shape to that of another.
- As a matt-white surface of A large screen cannot achieve an adequate picture luminance, screen surfaces have been developed with a partial specular reflection to increase luminance.
- The centre of the screen should be on the central axis of the auditorium seating, but it may be tilted from the vertical plane and set forward from the structural wall to provide a clear space of at least 3.4 m the loudspeakers.
- Mechanically adjustable black masking to the sides and top of the screen is normally provided to contain the picture surface and obtain maximum apparent brightness.
- The masking is usually wool serge on metal rails, and the gear should be fixed at floor level for ease of maintenance.
- Movement is remotely controlled from the projection room.
- Screen material is either PVC or metallised fabric, held by cord lacing to hooks on a metal lattice frame 460 to 920 mm larger than the maximum picture surface.
- The material needs to be flameresistant and is replaced at intervals.
- Sufficient space for manoeuvring a rolled replacement which could be 1 m in diameter will be necessary.
ix) Temporary screens
- In some multi-use auditoria screens may require to be easily and conveniently removed.
- A flat screen up to 6 m wide can be incorporated into a proscenium stage of a theatre form either housed, when rolled, in the stage or flown in the flytower.
- Curved screens could be flown, but take up much valuable space in the flytower; or they could be stored at the rear of the stage if fitted with rollers or castors for ease of movement.
x) Speaker installation
- The speakers need to be located behind the screen, firmly fixed to the platform or screen frame.
- One speaker is needed for monophonic sound; for multi-channel and stereophonic sound from 35 mm film, three speaker units are necessary: one centrally placed and the others equidistant from it.
- 70 mm sound production requires five symmetrically placed about the central speaker.
- In future, apart from mono-optical sound reproduction, the Dolby stereo optical sound system in 4-channel technology is also necessary with three loudspeaker combinations behind the screen and the fourth channel with additional speakers to the side and rear.
- For 70mm film 6-channel magnetic sound, the additional speaker combination is behind the screen.
- In the case of BTX, there is a sound absorption wall behind the screen according to the Lucas Film System into which the loudspeaker combination is built.
- Ticket offices are now superseded by electronic booking and reservation systems.
- The back of the screen frame, including the speaker, needs to be covered with heavy felt to absorb sound.
- The screen is set over a platform with a forestage, carpeted with black carpet to prevent reflection of sound and light.
- The forestage edge can be vertical, splayed or stepped.
- Screen curtains usually move horizontally on rails supported by steel tubes.
- Curtains overlap at centre when closed, and space is required either side of the screen when open.
- Alternatively they can be vertical festoon curtains.
6) Projection suite
- A suite may include the following spaces.
- Manual operation has been mainly replaced by automatic or remote control in commercial cinemas.
- New developments will require changes in the layout of equipment and this needs to be considered in the design.
7) Projection room
- Film projection: Fire separation materials are no longer required for the projection room with safety film.
- Projectionists operate several projectors; the projection room is no longer a continuously used workplace for staff.
- 1 m of space behind the projector and at the operating side, 2.80m high, ventilation, noise insulation to the auditorium side.
- Projection rooms may be combined for several auditoriums.
- A projection room is not required for 8 mm film but is a statutory requirement for 16 mm, 35 mm and 70 mm film.
- Controls the film timing, focusing and direction
- Regulates the volume and tone of sound reproduction
- Adjusts the masking
- Plays music from records or tapes during intervals
- Controls house lights and screen curtains
- Repairs, replaces and rewinds film, and
- Takes charge of all technical equipment.
The minimum sizes of projection rooms are:
- Minimum equipment: 3.9 × 4 m,
- With effects lantern and spotlight: 3.9 × 7.5 m,
- Typical commercial cinema: 6.6 × 7.3 m.
Floor-to-ceiling height should be not less than 6.4 m.
Equipment for commercial cinemas includes:
- Either two projectors or one projector with long-running equipment. Long-running projectors are common in multiauditorium complexes, with projecting covered by one projectionist moving from one cinema to another
- Effects lantern which may double as a spotlight
- Music table: non-synchronous music desk with tape-deck, storage and possible record player
- Rewind bench for the rewinding and storage of film having been shown: 600 × 1200 mm minimum and 914 mm high. If inflammable film, then a separate room for re-winding and storing films is necessary
- Amplifier. Unless there is a remote control system, controls and change-over switches are fitted between projection ports. Racks may be located against side or rear walls with rear access requiring a 500 mm space for maintenance. Three amplifiers may be necessary for stereophonic sound reproduction, with monophonic sound only requiring one amplifier and a power pack
- Spares cabinet; and
- Fire extinguishers.
- Each projector, effects lantern and follow spot, needs a separate port with optical quality glass through the wall between projection room and auditorium, as shown in the figure.
- Each projectionist also requires an observation port with plate glass.
- In cinemas with flammable films all ports require fire shutters releasable from either the projection room or the auditorium.
9) Layout of equipment
- A layout is shown in the figure below.
- Twin projectors are usually at 1.5 m centres with a 1 m workspace between.
- Other pieces of equipment are shown in figure below.
Power supplies for projectors.
- 8 mm and 16 mm portable equipment require a domestic 13 A power socket outlet.
- For 35 mm equipment with arcs up to 45 A, a single-phase supply is required.
- Above this, a three-phase supply is necessary.
- Lighting: no light should be directed towards the screen through ports.
- Task lighting at equipment during performances, general lighting for cleaning and maintenance.
- Ventilation: the projection room, rewinding room and associated lobbies need ventilation systems separate from the auditorium, with steady volumes of air at low velocity.
11) Associated accommodation
- Staff room: a separate room for projectionist adjacent to projection room, with sink and tea – and coffee making provision
- Toilet with convenient access for projectionist
- Workroom and store: a separate room for repair and maintenance of films and equipment adjacent to projection room
- Lobby: sound and light lock between projection suite and access corridor
12) Dimmer and switchroom
- If the dissipated power from dimming lights does not exceed 5 kW the dimmers may be in the projection room.
- If greater, then a separate room will be necessary for the dimmers associated with the switchroom.
- Automatic control allows controls to be remote from the projection room, with a separate room located in the auditorium such that the operator has a clear view of the screen: 2 × 2 m minimum size.
13) Car parking space
- Normally one per 5-10 spectators.
Overall, a successful cinema design requires a thoughtful approach that considers the needs of the movie-goers, the latest technologies, and the aesthetics of the space.