1、BRITISH STANDARD BS 5550-6.5: 1984 ISO 6035:1983 Cinematography Part 6: Television usage Section 6.5 Specification for the colours, luminances and dimensions for viewing conditions for the evaluation of films and slides for television UDC 778.5:621.397:778.584BS5550-6.5:1984 This British Standard, h
2、aving been prepared under the directionof the Cinematographyand PhotographyStandards Committee, was published underthe authority of the BoardofBSI and comes intoeffecton 30 November 1984 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CPM/1 Draft for
3、 comment 80/62432 DC ISBN 0 580 14141 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Cinematography and Photography Standards Committee (CPM/-) to Technical Committee CPM/1 upon which the following bodies were represented: Association
4、 of Cinematograph, Television and Allied Technicians British Broadcasting Corporation British Film Institute British Kinematograph, Sound and Television Society British Photographic Association Cinematograph Exhibitors Association of Great Britain and Ireland Independent Television Companies Associa
5、tion Institute of Amateur Cinematographers Amendments issued since publication Amd. No. Date of issue CommentsBS5550-6.5:1984 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 References 1 3 Colour and luminance of open ga
6、te screen 1 4 Screen dimensions 1 5 Illuminated surround 1 6 Ambient conditions 2 7 Review room for large audiences 2 Annex A Additional data 3 Figure 1 Table 1 Publications referred to Inside back coverBS5550-6.5:1984 ii BSI 10-1999 National foreword This Section of this British Standard has been p
7、repared under the direction of the Cinematography and Photography Standards Committee. It is identical with ISO6035:1983 “Cinematography Viewing conditions for the evaluation of films and slides for television Colours, luminances and dimensions”, published by the International Organization for Stand
8、ardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially
9、to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “Section of this British Standa
10、rd”. Cross-references. The Technical Committee has reviewed the provisions of ISO2895, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this Section of this standard. A related British Standard to ISO2895:1974is BS5550 “Cinematography” Subs
11、ection7.2.1:1978 “Specification for screen luminance in cinematograph laboratory and studio review rooms”. ISO6036, referred to in 3.4, is at present at the stage of draft. Since the reference constitutes informative matter only, the validity of this Section of this standard is not affected. A Briti
12、sh Standard covering similar subject matter to that dealt with in ISO6036is BS5550 “Cinematography” Section 6.4:1980 “Recommendations for the density range, contrast and colour balance of films and slides for colour television”. Additional information. Attention is drawn to the fact that there is a
13、revision of ISO2910 “Cinematography Screen luminance for the projection of motion-picture prints in indoor theatres and review rooms”, at present at the stage of draft, which incorporates the contents of ISO2895. ISO2910:1974is technically related to the following Subsections of BS5550 “Cinematograp
14、hy” concerned with the subject of screen luminance. Subsection 7.2.1:1978: Specification for screen luminance in cinematograph laboratory and studio review rooms; Subsection 7.2.2:1978: Recommendations for screen luminance for the projection of16mm film; Subsection 7.2.3:1978: Specification for scre
15、en luminance for the projection of35mm film on matt and directional screens; Subsection 7.2.4:1978: Specification for screen luminance for the projection of70mm film on directional screens. When the revision of ISO2910is published, it is likely that it will be published as an identical British Stand
16、ard, as a Subsection of BS5550, and that Subsections 7.2.1 to 7.2.4 of BS5550 will be withdrawn. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard doe
17、s not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. Thi
18、s will be indicated in the amendment table on the inside front cover.BS5550-6.5:1984 BSI 10-1999 1 1 Scope and field of application 1.1 This International Standard lays down the necessary conditions for the colour and luminance of open gate screen illumination and colour and luminance of the surroun
19、d illumination. It also specifies the relative size of the surround and screen, and the level of ambient illumination to permit critical evaluation of colour balance and contrast of films intended for television use. 1.2 This International Standard also recommends viewing conditions for review rooms
20、 for large audiences. 2 References ISO 2895, Cinematography Screen luminance for review room projection of motion-picture film intended for indoor theatres. ISO 6036, Cinematography Colour films and slides for television broadcast Density 1) . 3 Colour and luminance of open gate screen 3.1 Although
21、it is recognized that ultimate reproduction of white in the television system will be D 6500or illuminant C, a screen chromaticity and spectral distribution approximately that of a black body of nominally5400 K shall be used. A range from5000 to 6500 K is acceptable with a preferred characteristic o
22、f5400 K whenever it can be achieved. 3.2 The screen colour mentioned in3.1 results from chromatic distribution of the projector light and of the screen reflectance. (See annex A.1.1.) 3.3 To facilitate the illumination of a visual surround, it may be desirable to use a screen of low reflectance, or
23、one with directional properties. (Seeannex A.1.2.) 3.4 The open gate luminance of the screen measured in accordance with ISO2895shall be137 13,7 cd/m 240 4ftL 2) . This luminance will produce, with a film conforming to that specified in ISO6036, in the gate, a white luminance of about68cd/m 2 (20ftL
24、), which corresponds approximately to peak white luminance of colour television monitors. 3.5 The luminance at a distance of5% of the screen width from the side edges of the screen shall be90 10% of the centre luminance along the horizontal axis. 3.6 If a directional screen is used, the viewing audi
25、ence shall be restricted to that area from which the luminance tolerance is operative. 4 Screen dimensions 4.1 The viewing screen shall be of such size that the viewing audience may be seated at a distance from the screen equal to four to six times the screen height. Its size shall be sufficiently s
26、mall so that a visible surround area of approximately eight times the screen area is possible (see the Figure). 4.2 The ratio of screen width to screen height shall be1,33 : 1. Table 5 Illuminated surround 5.1 Illuminated surround is defined as the light, visible to the observer, which surrounds, bu
27、t does not include the central screen area. 5.2 The area of the illuminated surround shall be preferably at least eight times the screen area (seethe Figure). 5.3 The luminance of the illuminated surround shall be approximately 1/6to1/10the open gate screen luminance (see annex A.2.1). 1) At present
28、 at the stage of draft. 2) ftL = foot-Lambert. Figure Ratio of diamensions A 1,00 B 3,00 C 1,33 D 4,00BS5550-6.5:1984 2 BSI 10-1999 5.4 The colour of the illuminated surround shall match that of the open gate screen illumination to within 200K (see annex A.2.2). 6 Ambient conditions 6.1 The level of
29、 light shall be insignificant in comparison with that of the screen illumination and surround. 6.2 Light falling on the screen which is reflected to the viewing position shall be low enough so that the luminance of the projection screen measures less than3,4cd/m 2(1 ftL). To achieve this, walls shou
30、ld be of low reflectance. 6.3 The viewing room “decor” should preferably give a generally neutral impression without dominant colours being employed. 7 Review room for large audiences When the audience size exceeds the capacity of the review room described, and the specified conditions cannot be mai
31、ntained, the evaluation and impression of the characteristics of the film may change. Large audience review conditions for theatrical purposes then apply to the review characteristics as described in ISO2895. When these conditions exist, the user is cautioned that the elimination of a lighted surrou
32、nd reduces the viewers sensitivity in making judgment of contrast.BS5550-6.5:1984 BSI 10-1999 3 Annex A Additional data (This annex forms part of the standard.) A.1 Screen and projector characteristics A.1.1 The desired colour may be obtained using an arc source in the projector. The high intensity
33、carbon arc usually operates at close to5400K. The xenon arc will operate closer to6000K when new, and may change toward5000K with age. Another method is to use a blue photometric filter having a mired shift value of approximately 110units with a projector having a tungsten source, changing its nomin
34、al colour of about3500K to5400K. A mired shift of minus 110units may be obtained by the use of a suitable thickness of blue glass photometric filter such as Corning Filter No. 5900. The use of gelatin filter is not recommended. Colour temperature may be verified most easily by comparison with a know
35、n reference of5400K by measurement using a spectroradiometer. Two- or three-colour temperature meters may not give relative results with xenon illumination or other sources which depart from black-body spectral quality. Another method is to use a tungsten light source equipped with a blue photometri
36、c filter of such a thickness as to produce a nominal colour of approximately5400K. A.1.2 The choice of screen material will depend on the projection illumination available and the method chosen to provide surround illumination. If the projection source is tungsten, filtered to5400K by a supplementar
37、y filter over the lens, a directional, high-gain screen may be required to provide sufficient open gate screen luminance. If the source is a xenon arc capable of a beam output of the order of100lm, a matt white screen can be used. If500lm are available, a20% reflection grey screen can be used. Both
38、the20% matt grey screen and the directional high-gain screen make it possible to achieve the desired black level on the unlighted screen, in the presence of some ambient light. This practice does not preclude the use of rear projection screens, provided uniformity of illumination can be achieved. Fo
39、r aesthetic reasons, a screen mask or border may be desired. If used, it should preferably be confined to a width not exceeding4% of picture width. A.2 Light surround A.2.1 To judge contrast in the film, the level of surround luminance ideally should approximate average picture luminance. This is mo
40、st frequently about1/5the picture white luminance, although it can vary widely. However, for optimum sensitivity of the observer to colour casts and colour balance errors, a higher surround brightness is required and a value of1/3the picture white luminance is frequently used, although this may be f
41、ound tiring to the observer in long review sessions. Ideally, the surround brightness level should be adjustable, but if a single-valued compromise is adopted, it should lie between the limits1/6to1/10of the open gate screen luminance, i.e., 1/3to1/5picture white luminance for a typical print. The l
42、evel may be measured directly or it may be checked relative to screen luminance by placing the appropriate value of neutral density, non-scattering filter over the projection lens. This attenuates the screen luminance by the required factor allowing a visual match with the surround. A.2.2 It is impo
43、rtant that the surround match the screen for colour. The use of a0,6density non-selective, non-scattering filter over the projector lens, permitting a visual match of screen with surround, is the easiest and most accurate way to verify such a match. It is necessary, however, that the filter used int
44、roduces no colour. A filter of evaporated metal, such as Inconel, can fill this requirement. Surround illumination may be obtained in several ways. It can be a transilluminated panel. Front illumination can be used provided the screen itself is not lit. This can be achieved by placing the screen in
45、a plane in front of the surround plane, with surround lights behind the screen. It can also be achieved by projecting surround light with specular optics, masking out the screen area. Or, it can be achieved if a directional, high-gain screen is used, by appropriate placement of overhead light, using
46、 readily available fluorescent tubes operating at a nominal colour temperature of5400K. A.2.3 When problems in room design prevent achievement of the full surround format and geometry, some compromise in uniformity of surround illumination and in centring of the screen in the surround area may still
47、 permit the essential performance of this review room.BS5550-6.5:1984 4 BSI 10-1999 A.3 Compatibility A.3.1 Experiments have established that the same colour balance and density for prints is preferred under the larger screen, darkened room condition as under the smaller screen, lighted-surround con
48、dition. However, it is possible, because of the visual adaptation, for an observer in the darkened room to judge as acceptable some prints which would be recognized as less acceptable or unacceptable in the presence of the lighted surround.BS5550-6.5:1984 BSI 10-1999 Publications referred to See nat
49、ional foreword.BS 5550-6.5: 1984 ISO 6035:1983 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products a
