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C.S.T. TECHNICAL SPECIFICATIONS – June 2001 CST-RT-002-P-2001-english

''DIGITAL CINEMA'' TYPE ELECTRONIC PROJECTION ROOMS Document used within the framework of the CST Technical Approval for the Operator Licences delivered by the National Cinematography Center (Regulation Decision n°12)

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TABLE OF CONTENTS 1/ FOREWORD

PAGE 3

2/ DEFINITIONS

PAGE 4

2.1 ELECTRONIC PROJECTION ROOMS 2.2 DIGITAL CINEMA ROOMS 2.3 TECHNICAL RECOMMENDATIONS

3/ GENERAL

PAGE 5

3.1 OBJECT 3.2 SCOPE OF APPLICATION

4/ DIMENSIONAL CHARACTERISTICS

PAGE 6

4.1 IMAGE FORMATS 4.2 DIMENSIONS OF SCREENS – SEATS LAYOUT ZONE

5/ SPECIFICATIONS – TECHNICAL CHARACTERISTICS

PAGE 13

5.1 CONDITIONS OF IMAGE PROJECTION 5.2 PROJECTION ROOM ACOUSTICS

6/ BIBLIOGRAPHY

PAGE 20

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C.S.T. TECHNICAL SPECIFICATIONS DIGITAL CINÉMA" TYPE ELECTRONIC PROJECTION ROOMS

1/ FOREWORD The present document constitutes an update of the ''Video Technical Specifications'', issued by the "Commission Supérieure Technique" (CST hereinafter) in 1982, within the framework of the Technical Approval delivered by the CST to the Operating Department of the National Cinematographic Center (CNC hereinafter). This Technical Approval forms part of the set of documents needed to obtain the Cinematographic Operation Licence, as per the terms of the Regulatory Decision n°12 of the CNC. This Technical Approval applies to cinematographic projection rooms regardless of their type, i.e. silver or digital. The Technical Specifications that apply to conventional silver film projection are embodied in the Cinematographic Operation Technical Assistance Guide, issued by the CST in 1994, updated 1998. This document also provides useful information concerning the design of projection rooms in order to achieve satisfactory operating conditions. The domain of electronic projection has been marked by significant technological evolutions which have led to the updating of the video specifications. The present document specifies the mandatory values ‘’at minima’’ for the equipment of the cinema theaters provided with electronic projection equipment in order to meet the designation ‘’DIGITAL CINEMA’’, and thus to be taken into account upon completion of the terms of the CST Technical Approval described above. Another document shall be issued by the CST, which will embody all the technical specifications associated with the utilization of electronic projection equipment not intended for the diffusion of films, hence not within the framework of CNC Operators Authorizations. These are mainly event-based projections or others, which are not concerned by CNC ticket saling. The choice of the terms ''Digital Cinema'' is a deliberate one intended to define, today, the leading edge of technical quality in electronic projections. Indeed, the quality of the results obtained with digital technologies today is second to none in terms of digital processing of electronic images, storage, transfer and screening. One of the objectives is to guarantee that the viewers in Digital Projection Rooms (DPRs hereinafter, the definition of which is given below), shall enjoy a quality of projection of cinematographic works that shall not affect the artistic aspect thereof. Therefore, in order for the artistic dimension of the work to be respected, the technical quality of the screening technologies shall not be technically lower that the quality achieved with conventional silver films, in terms of physical size and durability. If, in the future, other technologies, be they analogical or other, should guarantee qualitative results at least equal or even higher, the present document would then be updated accordingly. For this reason, the validity of the present document extends over the period from January 1, 2001 to December 31, 2003. The texts will be updated at this date, taking into account the technological evolutions observed at the end of this period of time. Then, either the present document will be simply renewed (no significant technological innovation), or new technological features will be included in an updated version. CST - 11, rue Galilée - 75116 PARIS - Tél. : 01 53 23 90 80 - Fax : 01 47 23 09 94 - E-mail : [email protected] - URL : http://www.cst.fr Association loi 1901 - SIRET 78433300700028 - Code APE 743 B - Code TVA FR96784333007

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2/ DEFINITIONS The following definitions are proposed and shall be in force hereinafter:

2.1 - Electronic Projection Rooms The term "Electronic Projection Room" applies to any room able to screen images recorded on ''electronic'' medium, in either an analogical or a digital (magnetic, computer system , etc.) form.

2.2 - Digital Cinema Rooms The term "DIGITAL CINEMA ROOM" applies to any ''electronic projection'' room able to screen images recorded on an ''electronic'' medium (magnetic, computer, etc.), as DIGITAL-type information, while meeting the quality criteria defined in the present document (see Chapter 5). These images shall be digital, ''high definition'' type or higher, and stored on a digital medium (see technical definition of the term hereinafter). Only the rooms which meet the criteria stipulated in paragraph 2.2 above shall receive the Technical Control Certificates delivered by the CST to the Operation Licencing Departments of the National Cinematographic Center (Statutory Decision n°12).

2.3 - Technical Recommendations The CST publishes a document titled “TECHNICAL SPECIFICATIONS – DIGITAL CINEMA-TYPE ELECTRONIC PROJECTION ROOMS’’, that embodies all the technical specifications applicable to Digital Cinema-type electronic projection rooms. These criteria could be supplemented by Technical Recommendations from the CST on ''Electronic Projection'', applicable to cinemas whose programs are limited to screening ''events'', excluding all forms of cinematographic work. These documents shall be included into the ‘’Operation Technical Assistance Guide’’, that the CST publishes since 1994, regularly updated, and which already specifies the whole spectrum of technical specifications concerning the projection of conventional films, together with the general technical conditions for the operation of cinema theaters (sound, specific provisions, etc.).

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3/ GÉNÉRAL 3.1 - Object The present Technical Specifications define the dimensional and technical characteristics of ‘’Digital Cinema’’ electronic projection rooms. They set forth the various quality levels which correspond to the definitions in chapters 1 and 2. It is reminded that these characteristics shall, moreover, comply with the criteria stipulated in the latest issue of the Regulation ''Fire Safety in Public Premises'', published in the "Journal Officiel de la République Française".

3.2 - Scope of application The present Technical Specifications define two elements : · the format of the images transmitted to the electronic projector. The ''artistic'' quality of the images which form the program does not fall within the scope of application of these Specifications. Only the format of the final file that is used for the projection is taken into account.

· the technical performance of the projection equipment. All the present or future screening technologies (transfer and projection), that enable the stipulated results to be achieved, are accepted.

4/ DIMENSIONAL CHARACTERISTICS The present chapter is a transposition to digital projection of the stipulations of French Standard AFNOR NF S 27001 "Dimensional Characteristics of Cinematographic Theaters", which is used as a reference within the framework of Regulatory Decision n°12 that lead the deliverance of Operation Licences of the CNC. It defines the set of architectural requirements needed to provide satisfactory convenience to any viewer in a cinematographic projection room. The definitions used enable full compatibility with French Standard NF S 27001, on the basis of equivalent dimensions of images.Thus, a room that meets the requirements of this standard could be upgraded to become an electronic projection room without additional works.

4.1- Image Formats 4.1.1 Définition The format of an image is given by the width-to-height ratio of the projected images.

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4.1.2 Formats In “digital cinema’’, the systems must be designed to project all images formats ranging from the Format 4/3 (equivalent to the format 1.33) to the Cinemascope format 2.35, including all the standardized formats with the existing media (conventional films, ISO Standard 2907, or video). The formats in electronic projection are as follows: · Format 4/3 equivalent to the format 1.33 · Standard format 1.37 · Panoramic format 1.66 · Format 16/9 equivalent to the format 1.78 · Panoramic format 1.85 · Cinemascope format 2.35 Any subsequent format shall meet the present Specifications, i.e. they shall comply with an international standard and that they shall correspond to a production format.

4.2- Dimensions of Screens - Seats Layout Zone The seats layout zone shall comply with the location shown below as a function of the dimensions of the screen. Note that in electronic projection, curved screens should not be used since the depth of field of the optical projection systems used do not guarantee a correct image definition over the whole surface of a curved screen. This defect cannot be electronically corrected on post-produced images. This specification does not apply to specific projections similar to hemispheral-type projections using silver medium.

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L : width of screen in 16/9. For a 4/3 screen format, the calculation of P and D is made on the width of a 16/9 screen calculated on the height of 4/3 screen.

P : minimum distance screen-to-first row D : distance maximale séparant l'écran du dernier rang D' : maximum permissible distance screen-to-last row a : maximum obliquity angle

icticiousv 2,35" scope screen

a Screen16/9 screnn 4/3

L

seating zone

a

P

D D'

Figure 1 : Seating Zone Layout

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4.2.1 - Screen-to-Seats Distance 4.2.1.1 - Screen / 1st Row The minimum viewing distance of electronic images is related to the ''native definition'' of the images. The higher the definition, the closer the position of the first viewer. The minimum distance is, however, also limited by the preception of the image global field (solid angle of perception).

Minimum distance Screen/1st row

P ³ 0.8 x L16/9 P ³ 0.6 x L 2,35

Refer to the C.S.T.Operation Guide for further information on the motivation of these values.

4.2.2.2 - Screen / Last Row The maximum vision distance of the images concerns the ability of each viewer to perceive the finest details of the projected image, and to look at an image which covers at least 20° of the field of vision (see explanation in Chapter B and C.2 of the Operation Guide).

Maximum distance screen/last row

D £ 3.3 x L16/9 or D £ 2.9 x L 2,35

The maximum ratio 3.8 x L16/9 is acceptable for the layout in an existing cinematographic projection room.

4.2.3 - Heads Tilting Angle The following value takes into account the human physiological and psychological abilities (see Operation Guide). They determine the maximum image perception angle above the field of vision along the axis of view. It corresponds to a position of the eyes 1.10 m (» 3ft2) above ground.

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H/2 H H/2

b h

A

D

Figure2 : Heads tilting

Maximum head tilting angle towards the top of the screen

b £ 45°

Maximum head tilting angle towards the center of the screen

30°

4.2.4 - Seat Rows Pitch The seat rows pitch will be measured at the feet of the seats, the tilting of the backs being too irregular to be used as a reliable unit of measurement. This value should guarantee a pleasant comfort for the viewers.

Minimum distance between two rows Floor with continuous profile Floor with steps

0.80 m (» 3 ft) (0.90 recommended) 0.90 m (» 3 ft)

4.2.5 - Lateral angle of vision This value defines the maximum seat-to-screen lateral offset. It gives the angle formed by a straight line which links the edge of the screen to the axis of the most offset seat, with the straight line perpendicular to the edge of the screen (see figure 1). The value given below is based on a 2.35 cinemascope screen calculated on the height of a 16/9 screen. In the case of a screen 4/3 only, the calculation is based on the 16/9 screen of equal height (see Operation Guide C.2.4).

Maximum offset angle a

a £ 20°

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4.2.6 - Orientation of the seat back planes The plane of the backs of the seats will be oriented along a direction comprised between the plane that runs parallel to the screen and the plane that runs perpendicular to the vision axis to the center of the screen for the seat considered.

D normal orientation angle a

E

Screen Maximum orientation angle Parallel plane Perpendicular plane to the screen to vision axis the center of the screen

Figure 3: orientation of the planes of the seat backs Orientation of the plane of the seat backs

a £ atg (E/D)

4.2.7 - Heads clearance The head clearance defines the ability of a viewer to look satisfactorily at the screen over the head of the viewer(s) in front of him. The basic criteria is that the viewer should see the whole screen, without amputation or discomfort. The mathematic equations below enable calculating either the head clearance values as a function of the levels of the rows, or the levels of the rows as a function of head clearance value sought. The head clearance for a given profile is calculated as follows:

t =

(c * ( z -

y +

h

2

-

h

1

) -

(c +

p * ( h

1

+

y -

a ))

p )

The ground profile is calculated as follows:

Z =

(c * ( y + h1 - h 2 )) + p * ( h1 + y - a ) + t * (c + p )

c

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P Row n+1

S c re en

C R ow n t

H

A Z

Y

R e feren c e lev e l

Figure 4 : Head clearance The following equation gives the head clearance for a given profile: t =

(c * ( z - y ) - p * ( h + (c + p )

y - a ))

The following equation gives the ground profile with a desired head clearence : Z =

( c * y ) + p * ( h + y - a ) + t * ( c + p)

c

On the basis of the eye of the viewers at 1.10 m (» 3ft2) from the ground (H value in the equation), the mean ''physiological'' value (which corresponds to the distance betwee the eye and the top of the head), is 0.12 m (» ½"). Taking into account the defects inherent with the construction of floors, sometimes unavoidable (inaccurate dimensions, concrete variations, etc.), profiles should be calculated on the basis of a minimum value of 0.15 m (1.6"), if the ceiling clearance is limited, or higher if this problem does not exists. Modern seats in cinema theaters are so designed that the eye of the viewer is at 1.10 m (» 3ft2) from the ground. The H value applicable to this type of seat should be integrated in the ground profile design.

Minimum head clearance value

³ 0.12 m min. (4.72 inch)

³ 0.15 m recommended (5.9 inch)

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4.2.8 - Location of the projector Certain electronic projection systems include correction menus for the geometrical deformation of image related to lateral or vertical (top) shots. These menus have limited scopes of application. It is essential to refer to the characteristics of the equipment selected in this domain. Whatever the case, it is recommended to place the projector in the zone materialized by the lines that run perpendicular with the edges of the screen (see figure 5). In the case where it is not possible to place the projector within these limits, the geometrical deformation rate of the images, calculated as for a cinematographic projection (see Operation Guide C.3.2), shall be limited to the data below. The following equation is used for the calculation: D % = 200 x tg a x tg (b/2) where a is the vertical shot angle (projector to the center of the image) and b is the opening angle of the projection beam (projector to the edge of the image).

Layout limits of electronic projector

Screen

Layout limits of electronic projector

Screen

Figure 5: Location of electronic projectors

Geometrical deformation of images

£ 3%

Moreover, certain provisions shall be applied to guarantee that the equipment will operate satisfactorily, namely in terms of cooling, hygrometry control and heat dissipation and disposal.

4.2.9 - Overhead clearance under the projection beam This parameter shall guarantee that the body of a viewer walking anywhere in the room will not interfere with the projection beam, especially with the head, thus creating a shadow that could hide part of the image.

Overhead clearance under the projection beam

³ 2.00 m

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Optical axis

O/head clearance under beam

Figure 6: Overhead clearance under the projection beam The position of the projector in the projection booth will therefore comply with the provisions of specifications 4.2.7 and 4.2.8. As to the vertical clearance under the projection beam, the tolerance values proposed in standard NF S 27001 concerning low capacity room also apply.

5/ SPECIFICATIONS - TECHNICAL CHARACTERISTICS The values indicated below define the minimum technical characteristics that electronic projection equipment must comply with for ‘’digital cinema’’ operation. They are recorded in situ as per the methodology described herein. The points specified below are only those considered as necessary to guarantee that the theater technical equipment will make it possible to propose a ‘’DIGITAL CINEMA’’-type image quality.

5.1 - Conditions of image projection Prior to any quantitative measurement of the quality of the images projected, the equipment must be set and tuned using the ANSI SETUP MEASUREMENT pattern. Any measurement made without this presetting cannot be validated.

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B/2

B/2 X1 = B/10 X2 = H/10

L5

L3

H

L1

L2

L4

X2 X1 B

Figure 9: Measurement Points 5.1.1 - Luminance of images

Þ Object In relation to the way light is perceived by the eye (colorimetry, definition, etc.), the images must have a minimum luminance or brightness.

Þ Measurement method Standard ANSI - NAPM IT 7.227 - 1996 defines the measurement methodology for the illumination provided by the source. This measurement concerns the luminance of the images, i.e. the brightness of the surface of the screen. Hence, a 100% white pattern is used over the whole surface of the images. The measurement is taken using a luminancemeter with a 1° measurement angle. The observer takes position in the back third of the seating zone, along the center line of the screen. In the case of directive screens, the measurement is repeated on either side of the screen center line, at a distance which corresponds to 1/3 of the width of the row of seats.

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Unlike the measurement methodology used for 35 mm projectors, in which luminance is measured without the film in the corridor (then only the light source, the objective and the scree are measured and not the image medium), the image medium cannot be removed in the ‘’digital cinema’’ projection (i.e. in the micro-mirror technology, the matrix is the image medium). Therefore, considering the work already carried out by CST to date, and completed by technical information supplied by the manufacturers, there is no systematic analogy between the luminance values in 35 mm projection and in digital projection.

Þ Specification Luminance of images at the center Tolerance

30 cd/m² 20 to 55 cd/m²

5.1.2 - Difference in luminance Þ Object Beyond the illumination uniformity, which is only an average value, the difference in luminance between two zones of the screen must be minimized. Regardless of the conditions, the brightest spot should be the center of the images, this applying to all the viewers.

Þ Measurement Method Thus, the ratio between the brightest spot and the least bright spot of the image is established. Difference (%) = (Lmin/Lmax) x 100

Þ Specification

Difference in luminance

³ 50 %

5.1.3 - Picture Definition Þ Object This aspect defines the minimum quality of the source medium and that of the projectors. Here, the difference between ''electronic projection'' and ''digital cinema'' is introduced. The ''digital cinema'' quality is defined (Chapter 2 – “Specifications” § 2.2).

Þ Measurement Method Two measurement methodologies are possible. The first one, derived from the methodology used in cinematographic projection, and from the first issue of the the Video Technical Prescription (1982), consists in having the pass-band of the signal projected from a pattern with a referenced definition assessed by a human observer. CST - 11, rue Galilée - 75116 PARIS - Tél. : 01 53 23 90 80 - Fax : 01 47 23 09 94 - E-mail : [email protected] - URL : http://www.cst.fr Association loi 1901 - SIRET 78433300700028 - Code APE 743 B - Code TVA FR96784333007

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This pattern should be bright enough to enable the pass-bands to be identified. The observer, who should have a correct vision, will be placed at 0.8 x L16/9 from the screen. The second method consists in using a pass-band optical analyzer, the definition power of which shall be at least twice that of the maximum definition of the projection systems. Moreover, at the date of issuance of these prescriptions, two technological families make it possible to project the required quality : projector with variable definition (without matrix), and projector with fixed resolution (with matrix). The pattern used for this test shall make it possible to evaluate the definition in the horizontal and in the vertical plane.

Þ Specification For the projectors with matrix, the characteristics of the matrix in number of pixels shall be as follows:

Minimum number of pixels of the projector with MATRIX

1920 pixels per line

Provisory tolerance, applicable during the transition period that precedes the implementation of the technologies 1920 x 1080 or higher

1280 pixels per line

For the formats with a ratio in excess of 1.5 (panoramic 1.66 and 1.85, cinemascope 2.35), an anamorphic projection optic device suitable for each format shall be provided, in order to use the whole height of the matrix. The projection of these formats as per the ‘’letter box’’ technique, i.e. which does not use the whole height of the matrix, cannot be accepted. For the projectors without matrix, the vertical and horizontal pass-band characteristics shall be as follows:

Minimum vertical pass-band

³ 12 MHz

Minimum horizontal pass-band

³ 30 MHz

The transmission media to the projection site, together with the storage and reading media on site shall also make it possible to transmit electronic signals which meet these characteristics.

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The estimation of the definition being done during the projection, the equipment used (source medium, projection system, projection lens, window, screen), shall make it possible for the viewers to perceive this definition

5.1.4 – Contrast Ratio Þ Object There are at least two causes for contrast reduction or limitation: · the technical characteristics of the projection equipment · the reflection of parasitic light on the walls of the room or the emission of parasitic light from auxiliary equipment (exit marking, etc.) There are different ways to approach the contrast of images: · either as the ratio between the luminance or illumination of black and white zones of an ANSI-type pattern · or the ratio between the luminance of a fully black image (0% over the whole surface) and the luminance of a totally white image (100% over the whole surface). In the present specification, the second solution has been selected. This methodology expresses the characteristics of the equipment in projection conditions; integrates the final dimensions of the images; and makes it possible to eliminate parasitic lights. The result expresses the ratio between white and black images (ci ‘’Methodology’’ below). Bearing in mind the measurement methodology used, the rate of parasitic light reflected by the walls or coming from annex light sources is not taken into account.

Þ Measurement Method The contrast ratio is measured at the scree using a luxmeter - hence in incident light type Minolta T1M or equivalent, located at the end of a mat black tube diameter 85 mm, 125 mm long. The measurement is carried out with a uniform black image (0% modulation), then white (100% modulation) produced by a source external to the projector.

Þ Specification In order to meet the so-called ‘’Digital Cinema’’ quality, the ratio of illumination measured shall comply with the following specification:

Black/white illumination values ratio

> 450

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5.1.5 – Rate of residual parasitic light Þ Object The objective is to evaluate the level of parasitic light emitted by ‘’annex’’ light sources: reflected from walls; signals, outside lights, etc.

Þ Method of measurement By projecting the ANSI black and white checkered pattern, an illumination measurement is taken on the blkack squares, which correspond to the measurement points indicated in figure 9. Then the ratio with respect to the illumination recorded in § 5.1.1. is calculated.

Þ Specification In order to comply with the so-called ‘’Digital Cinema’’ quality, the illumination level of the black checkered pattern shall not exceed the percentage below for the illumination of the adjacent white checkered pattern:

Residual parasitic light ratio with respect to the illumination of te white surfaces

£ 10 %

5.1.6 - Colorimetry of the Images Þ Object For the projection, it is essential that the color calibration of the images be respected. The colorimetry of the high definition systems (namely the reference monitors) is defined in recommendation BT.709 from UIT-R. This recommendation stipulates the use of reference white D65 whose color temperature is 6500°K

Þ Measurement method The measurement is carried out by projecting a 100% white pattern over the whole surface of the image. The measurement is taken using all the image ratios planned (at least 4/3 and 16/9), at the center of the image. For this, a thermocolorimeter adapted to the measurement on electronic type images will be used.

Þ Specification

Color temperature

6500°K ± 400°K

This value, within the tolerance limit of 400°K, will also be ensured at the five measurement points defined in figure 9, § 5.1.

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5.1.7 - Signal Processing Þ Object Several parameters must also be taken into account when assessing the quality of the signal. The latter undergoes a cerain number of processings (compression, decompression, transport, quantification, filtering, etc). There are qualitative assessment systems of digital images, namely for the control of the transmission systems. SO far, the only exhaustive document is the standard HDTV SMPTE 274M. The CST – FT – TDF platform is responsible for the development of all experiments intended to validate the methodologies selected, namely for satellite transmission. It is clear that the digital information transport and storage system to and inside the projection site should not affect or degrade the original quality of the computer files and of the artistic information.

5.2 - projection room acoustics The acoustics in projection rooms must meet criteria that enable unimpeded understanding of all the sound information associated with the image. These criteria concern the duration of the reverberation and the level of background noise. Notions on intelligibility (RASTI, etc.) can be integrated. The reference information are given in the ‘’Acoustics’’ chapter of the Operation Technical Assistance Guide published by the CST. The cinematographic projection theaters must also meet the standards and decrees in force in terms of sound impact on the neighbourhood (New Acoustic Regulation – Ministerial Decree, etc.).

CST - 11, rue Galilée - 75116 PARIS - Tél. : 01 53 23 90 80 - Fax : 01 47 23 09 94 - E-mail : [email protected] - URL : http://www.cst.fr Association loi 1901 - SIRET 78433300700028 - Code APE 743 B - Code TVA FR96784333007

COMMISSION SUPERIEURE TECHNIQUE DE L'IMAGE ET DU SON

CST - 11, rue Galilée - 75116 PARIS - Tél. : 01 53 23 90 80 - Fax : 01 47 23 09 94 - E-mail : [email protected] - URL : http://www.cst.fr Association loi 1901 - SIRET 78433300700028 - Code APE 743 B - Code TVA FR96784333007