इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 15357-2 (2003): Photography - Projection in Indoor Rooms, Part 2: Screen Luminance Test for Still and Video Projection [MED 32: Photographic Equipment] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” ..., 1 IS 15357 (Part 2) :2003 ISO 11315-2:1997 w? \ \ –W=mhm-widrawm I Indian Standard PHOTOGRAPHY— PROJECTION IN INDOOR ROOMS PART 2 SCREEN LUMINANCE TEST FOR STILL AND VIDEO PROJECTION Ics 37.040.10 0 BIS 2003 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADLJR SHAH ZAFAR MARG NEW DELHI 110002 June 2003 Price Group 4 .. *- .... ., - 1 Photographic Equipment Sectional Committee, ME 32 NATIONAL FOREWORD This Indian Standard (Part 2) which is identical with ISO 11315-2:1997 ‘Photography— Projection in indoor rooms — Part 2: Screen luminance test for still and video projection’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendations of the Photographic Equipment Sectional Committee and approval of the Mechanical Engineering Division Council. The text of ISO Standard has been approved as suitable for publication as Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’. b) Comma (,) has been used as adecimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker. ISO1131 5consists ofthe following other parts under the general title ‘Photography— Projection inindoor rooms’: Part 1 Screen illumination test for still projectors Part 3 Classification of transmitting projection screens and measurement of their transmitted luminance levels Part 4 Reflecting projection screens — Classification and measurement of reflected screen luminance levels and sound attenuationlj Inthis standard, reference appears to the following international Standard for which Indian Standard also exists. The corresponding Indian Standard, which is to be substituted in its place, is listed below along “withits degree of equivalence for the edition indicated: International Standard Corresponding Indian Standard Degree of Equivalence 1s0 11315-1:1997 IS 15357 (Part 1):2003/ ISO 11315-1:1997 Identical Photography— Projection inindoor rooms: Part 1 Screen illumination test for still projectors The concerned Technical Committee has reviewed the provisions of ISO 2910:1990,CIENo.15.2: 1986, CIE No.69: 1987 referred inthis standard and has decided that these are acceptable for use inconjunction with this standard, Annexes A and B of this part of ISO 11315 are for information only. 1,Tobe published. .. *..6-. “ ““- IS 15357 (Part 2) :2003 ISO 11315-2:1997 Indian Standard PHOTOGRAPHY— PROJECTION IN INDOOR ROOMS PART 2 SCREEN LUMINANCE TEST FOR STILL AND VIDEO PROJECTION “ 1 Scope This part of ISO 11315 specifies the measurement of screen luminance level, as seen by a (seated) viewer for all types of purely optical still projection in darkened projection rooms. Since the optical characteristics of the surface of this screen have a direct bearing on luminance, the screen shall be considered an integral part of the projection system for this part of ISO 11315. A standardized light-measuring system allows comparison of screen luminance values for different projection systems used alternately in practical use. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of 11315 . At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 11315 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid 1 International Standards. \ 1 ISO 2910:1990, Cinematography - Screen luminance for the projection of motion- picture prints in indoor theatres and review rooms. F 1s0 11315-1:1997, Photography - Projection in indoor rooms - Part 1:Screen I i//umination test for still projectors. CIE No. 15.2:1986, Co/orimetry (2nd edition). CIE No. 69:1987, Methods of Characterizing Illuminance Meters and Luminance Meters - Performance, Characteristics and Specifications. 1 IS 15357 (Part 2) :2003 ISO 11315-2:1997 3 Definitions For the purposes of this pad of ISO 11315, the following definitions apply. 3.1 luminance: The quotient of the flux leaving, arriving at or passing through an element of surface and propagated in directions defined by an elementary cone containing the given direction by the product of solid angle of the cone and the area of the orthogonal projection of the element of surface on a plane perpendicular to the given direction. [CIE-Publ. No. 17] 3.2 screen: A light-reflecting or light-transmitting surface with defined optical properties for the purpose of projection. In this pad of ISO 11315, screen means the screen-picture area of the complete installed projection screen only appropriate to the print format (slide) and projection system in use. 3.3 theatrical projection: An indoor public projection system (e.g. in multi-purpose halls, auditoriums of universities, cinemas, etc.) 3.4 viewing area: A limited area for the — preferably seated — viewers. It allows good viewing conditions independent of the relative dimensions of the projection screen area. (See annex A, A,5.) 3.5 still projection: All projection methods with one or more projectors for slides, overhead- projection transparencies, episcopic pictures for projection and transparent LCDS. 3.6 uniformity ratio, g2:The ratio of the lowest measured illuminance/luminance to the highest measured illuminance/lumi nance, e.g. /!.min/L~aX(x 100 in O/.). [CIE-Publ. No. 17] 4 Test method for determining the screen luminance The distribution of luminance over the screen surface from a complete projection installation (i.e. including projector and screen in a projection room) is influenced by impinging light generated by the projector (@by room lighting), and the properties of the screen. The luminance towards the viewing area is directly dependent on the angle of the reflected (or transmitted) light by the screen surface as well as on the viewing position. It is expressed as a curve by the luminance factor indicatrix (see note below). To achieve this, the luminance distribution shall be determined at three test points (see figure 1) for three selected viewing positions. NOTE — The luminance factor indicatrix will be covered in ISO 11315-4 which is being prepared. 2 is 15357 (Pafi 2) :2003 ISO 11315-2:1997 W t- i ~i t 1 2 3 I -c (=4 . I f V6W l/2w 5/6w Key w Width ofthe projected image h Height ofthe projected image NOTE — The final location ofrelevant test points isdetermined bythe screen ratioactually used during projection. Figure 1- Location of the test points (1 -2 -3) on the screen Luminance shall be measured from three positions of the measuring device in the viewing area (see figure 2, B-A-C) to three test points (1 -2 -3) on the screen. 5 Measurement of screen luminance 5.1 Preconditioning The preparation procedure shall be the same as for the measurement of screen illumination according to ISO 11315-1:1997, subclause 4.1. 5.2 Measuring device The screen luminance shall be measured with a luminance meter having a recommended field angle not greater than 1,5° and the spectral sensitivity of a Standard Calorimetric Observer (CIE-Publ. No. 15.2). The measuring inaccuracy shall not exceed & 10 %. The luminance meter shall comply with the requirements of class B (CIE-Publ. No. 69). 3 .. ,..,... IS 15357 (Part 2) :2003 ISO 11315-2: 1997 /--R ,’ Key w Screen width x Distance from screen tolast rowofseats { B-A-C Position ofmeasuring device R Last rowofseating Figure 2- Position of measuring device in viewing area 5.3 Position of measuring device in the viewing area The measurements shall be taken with the luminance meter located approximately 1 m above the floor on the longitudinal axis of the projection room in the centre of the main seating area and at a position 2/3 of the distance from the screen to the last row of seats. To ensure satisfactory performance in all parts of the projection room, measurements shall also be taken with the luminance meter located approximately 1 m above the floor at two points on a transverse line across the projectio n room, at a position 2/3 of the distance from the screen to the last row of seats (measured from the screen) and a distance of 1/2 of the screen’s width to each side of the longitudinal axis of the projection room. 5.4 Test points on the screen The screen luminance shall be measured as shown in figure 1at three test points (1 -2- 3). 5.5 Measurement of luminance in the centre of the screen (L2) The screen luminance is determined by the luminance value L2, measured at the central test point 2 orI the screen (see figure 1), and shall be measured from the test position A in the viewing area. 5.6 Measurement of luminance at points 1 and 3 The screen luminance at points 1and 3 is determined by luminance values L1and L3 measured from the test positions B and C in the projection room. This results in the following values: From position B: LIB and ~3B From position C: Llc and L3C 4 .. ,. *..,--- IS 15357 (Part 2) :2003 ISO 11315-2:1997 6 Uniformity ratio g2of screen luminance Calculate the uniformity ratio g2from the following equation: min.{LIB,LsB,LIc,Lsc,Lz } g2...——— max. {L1~,L~~,f.1c,L3c,Lz} x 1000’0 (calculated to one decimal place) 7 Test results Give the results of the test according tothis part of ISO 11315 inthe form of the example below. totest point on screen from position luminance cd/m2 -------------------- .........................................................---------------------- 2 (centre) A (centre) L2= ... -------------------------------------------------- .........----------------- ....................... 1 B LIB= ... 3 B L3B= ... 1 c Llc = ... 3 c L3C= ... -------------------------------.....---------------.----------.-.--------------Q- ------------------ uniformity ratio.gp = ... Y“ 8 Uniformity of luminance distribution Over the complete screen surfac e, the screen luminance shall appear to be even and substantially symmetrical about the screen centre. This shall be checked from multiple positions ofthe viewing area. 9 Frequency of measurement To account for changes inthe light-handling properties of a projection system inthe course of time (e.g. ageing ofthe lamp reflector, darkening ofthe bulb, misadjustment and reduction of the projection properties ofthe screen), itis recommended that the luminance measurement be repeated, at least inthe centre ofthe screen, at intervals of three months. 5