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है”ह”ह

IS 15357-1 (2003): Photography - Projection in IndoorRooms, Part 1: Screen Illumination Test for StillProjection [MED 32: Photographic Equipment]

IS 15357 (Part 1) :20031s0 11315-1:1997

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Indian Standard

PHOTOGRAPHY— PROJECTION IN INDOOR ROOMSPART 1 SCREEN ILLUMINATION TEST FOR STILL PROJECTORS

Ics 37.040.10

(1 BIS 2003

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

June 2003 Price Group 5

Photographic Equipment Sectional Committee, ME 32

NATIONAL FOREWORD

This Indian Standard (Part 1) which is identical with ISO 11315-1:1997 ‘Photography— Projection inindoor rooms — Part 1 : Screen illumination test for still projectors’ issued by the International Organizationfor Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendations ofthe Photographic Equipment Sectional Committee and approval of the Mechanical Engineering DivisionCouncil.

The text of ISO Standard has been approved as suitable for publication as Indian Standard withoutdeviations. 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 shouldbe read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practiceIS to use a point (.) as the decimal marker.

ISO 11315 consists of the following other parts under the general title ‘Photography— Projection in indoorrooms’:

Part 2 Screen luminance test for still and video projection

Part 3 Classification of transmitting projection screens and measurement of their transmittedluminance levels

Part 4 Reflecting projection screens—Classification and measurement of reflected screenluminance levels and sound attenuation’}

The concerned Technical Committee has reviewed the provisions of CIE No.15.2: 1986, CIE No.17.4:1987, CIE No.18.2: 1983, CIE No.69: 1987 reterred in thrs standard and has decided that these areacceptable for use in conjunction with this standard.

Annexes A and B of this part of ISO 11315 are for information only.

IS 15357 (Part 1) :20031s0 11315-1 :1997

Indian Standard

PHOTOGRAPHY— PROJECTION IN INDOOR ROOMSPART 1 SCREEN ILLUMINATION TEST FOR STILL PROJECTORS

1 Scope

This part of ISO 11315 specifies a laboratory measuring method for determining the utilised fluxof the projector and the uniformity of screen illuminance in darkened projection rooms for alltypes of purely optical still projection.

A standardized uniform light-measuring system allows comparison of screen illuminance valuesfor 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 ISO 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 ofISO 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

International Standards.

CIE No. 15.2:1986,

CIE No. 17.4:1987,

CIE No. 18.2:1983,

CIE No. 69:1987,

Co/orimetry (2nd edition).

/rrtemationa/ Lighting Vocabulary [Same edition as IEC 50(845):/ntemationa/ E/ectrotechnica/ Vocafxdary, Chapter 845: Lighting,]

The Bask of Physics/ Photometry.

Methods of Characterizing lllumirrance Meters and Luminance Meters -Performance, Characteristics and Specjficatjons.

1

IS I 5357 (Part 1) :20031s0 11315-1 : 1997

3 Definitions

For the purposes of this part of ISO 11315, the following definitions apply.

3.1 illumination: The application of visible radiation (light) to an object.[CIE-Publ. No. 17]

3.2 luminous flux; light output: The quantity derived from radiant flux by evaluating theradiation according to its action upon a selective receptor, the spectral sensitivity of which isdefined by the standard spectral luminous efficiencies.[CIE-Publ. No. 17]

3.3 utilised flux: The luminous flux received on one side of the reference surface.[CIE-Publ. No. 17]

3.4 still projection: All projection methods with one or more projectors for slides, overhead-projection transparencies, episcopic pictures for projection and transparent LCDS.

3.5 dark-room projection: An indoor room without any additional room lighting, except safety-Iights for steps, emergency exits, etc.

3.6 uniformity ratio, g2: The ratio of the lowest measuredmeasured illuminance/luminance, e.g. E~in/E~~X (x 100 in[CIE-Publ. No. 17]

illuminance/luminance to the highest%).

4 Preparation for photometric measurements

4.1 Preconditioning

Before the commencement of any test, the projector shall be conditioned by being kept under

the environmental conditions of the testing laboratory for at least 8 h.

4.2 Projector set-up (light path)

While making the tests, the projector shall be operated with its normal components (e.g. light

source, heat filter, condenser, lens), but without projection material (i.e. slides, films, etc. in thepicture area or aperture plate).

4.3 Voltage, current and frequencies

4.3.1 The projector shall be operated from an adjustable power supply adjusted to within* 0,5 0/0of the rated voltage of the projector,

While adjusting the supply for tungsten lighting or non-controllable discharge lamps, the voltageshall be measured at the supply socket to which the recommended power supply cord of theprojector is connected. The frequency of the power supply shall match the manufacturer’s ratingfor the projector.

2

IS 15357 (Part 1) :20031s011315-1 :1997

For controllable xenon-discharge lamps, the current shall be the nominal value (according tothe data of the lamp-manufacturer) * 0,5 %. In the case of xenon discharge lamps with arelatively vast luminous flux, the measurement shall be made through a highlight film(approximately D= 0,1-0,15 where D is the film thickness, in millimetres) and with half of thenominal current. The value of the nominal luminous flux shall be calculated from the aboveparameters.

4.3.2 If the projector (equipped with tungsten lighting or non-controllable discharge Iarr,ps) issuitable for use at different voltages and/or frequencies, the measurements for determining theluminous flux shall be made either at each adjustable voltage ~ 0,5 % and its related frequency,or at least at a selection of characteristic voltages and frequencies. When selecting the voltagesand frequencies, consideration shall be given to the main usage of the projector in practice, andthe conditions under which extreme differences of the test results might be expected. Themeasurements for determining the uniformity of screen illuminance can be made at any positionof the voltage selector with the respective line voltage * 0,5 Y. and the related frequency,

4.3.3 For determining the input voltage of the tungsten lamp, the voltage at the lamp holdershall be measured with the lamp operating, and after the time specified in 4.8 has elapsed.(When a lamp is provided by a switching power supply, use a true r.m.s voltmeter.)

4.4 Lamp adjustment

The lamp shall be adjusted in the projector according to the operating instructions.

4.5 CleanlinessThe optical elements of the projector shall be free from dust and other contamination.

4.6 Ambient temperature

The ambient temperature in the testing laboratory shall be 23 ‘C * 2 ‘C,

4.7 Projector alignment

The projector shall be positioned so that the projection of its optical axis is normal to the planeof the screen. (See annex A, note.)

4.8 Stabilization

If the lamp is fed via a transformer or a ballast resistance, the light measurements shall bestarted, at the earliest, 20 min after having switched on the lamp, running under normal testconditions. If the lamp is fed directly by the mains voltage, the measurements can be startedafter 5 min.

4.9 Ambient light

3

The illumination of the screen due to ambient light should not exceed 1 Y. of the screenilluminance due to illumination projected through the projector lens during the measurement.For the reduction of stray light, the use of a black screen is recommended.

IS 15357 (Part 1) :20031s0 11315-1 :1997

5 Light-measuring equipment

5.1 GeneralThe photometric properties of projectors are described

its uniformity on the projection screen (see clause 7),

5.2 Photometer

by the luminous flux (see 6.4.2) and by

The photometer used shall have a spectral response characteristic corresponding to theCIE 1931 Standard Calorimetric Observer as specified in CIE No. 15.2:1986 (E-1 .3.1). (Thisresponse correlates with the colour sensation of the human eye.)

A physical receiver shall assess the illuminance in accordance with the spectral luminousefficiency for photopic vision V(l) as specified in IEC 50(845):1987, term 845-01-22 orCIE Publ. No. 18. The illuminance shall comply with class B as specified in CIE-Publ. No. 69.

The effective diameters of the photo-electrical component shall be specified in the test results(see clause 8).

5.3 Use of light meterThe light-sensing element of the meter shall be positioned at the plane of the screen with atolerance of +20 mm and parallel to it so that it measures directly the incident projected light.

6 Measurement of useful luminous flux (light output)

6.1 The useful luminous flux is calculated from the average screen illuminance and therespective projection area.

6.2 The effective projection area (see figure 1) A = wx h

where

A is the effective projection area, in square metres;w is the effective projection width, in metres;h is the effective projection height, in metres.

A shall be confined by using a suitable mask positioned in the picture area and brought to focus(e.g. an empty slide mount).

6.3 For determining the average screen illuminance, the projected light shall be measured atnine points (Cl - ~2 - ~3 - ~4 - IZ5 - ~6 - ~7 - C8 - ~g) on the screen as shown in figure 1.

Do not deduct the unlighted corner areas (e.g. of an overhead projector) from the calculatedarea.

4

IS 15357 (Part 1) :20031s0 11315-1 :1997

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w Effectiveprojectionwidthh Effective projection height

Figure 1- Screen illuminance measuring points on the screen(for the selection of test points, see 7.3)

6.4 Calculating the useful luminous flux

6.4.1 The arithmetical average of the nine readings (EX) of screen illuminance is given by ~, inIux:

E= z:=, ..9

6.4.2 To determine the effective luminous flux of a projector, the illumination is measured at anumber of specified positions on the screen. A mean value (useful luminous flux) is calculated,which is then multiplied by the used area of the screen, in square metres.

The utilised luminous flux @ of the projector is given in lumens:

where A is the effective projection area on the projection screen w x h (see 6.2),

6.4.3 The effective projection area A shall be’in the range from 1 I?_#to 2 mz, In order todetermine the projection area used for the test, the normal usage for which the projector isdesigned shall be noted.

IS 15357 (Part 1) :20031s0 11315-1 :1997

7 Uniformity of screen illuminance

By combining the screen illuminance at various positions, the uniformity of its distribution on the

screen is established by the uniformity ratio g2.

NOTE — The highest measured illuminance Emax is normally measured at point Q (see figure 1).

7.1 Determining the uniformity of screen illuminanceFor determining the uniformity of screen illuminance, intensities of illuminance at differentcorner points are set in proportion to the intensity of the illuminance at the centre of the screen,

7.2 Alternative types of different measuring positionsThree different types of measuring points are defined (see figure 1) and any or all of them canbe used:

a) type 1: corner points

wh~1-~3-~7-~gat ——

6’10

(for all kinds of projectors);

b) type 2: corner points

whEIO-Ell-Ei2-E13at filfi

(for all types of slide projectors);

c) type 3: corner points

(for all types of slide projectors).

6

7.3 Calculating the uniformity of screen illuminanceFrom each type of corner point, the point with the lowest

IS 15357 (Part 1) : 20Q31s0 ‘11315-1 :1997

intensity of illuminance is chosen. The

illuminance value at this point is calculated as a proportion of the illuminance value at the centrepoint (E5).

The resulting vaiues, 92.6 or gp.lo or gp.po, serve as indications of the uniformity of screenilluminance:

Measuring position

Ea) type 1: 92.6 = “n(’’3’7’g) X1 OOYO

E5

(for all types of projectors);

E~in(,o, II, ,2, 13)b) type 2: 92-1o =

E5XI OOYO

(for all types of slide projectors);

Emin(ld,,5,,6, ,T}c) type 3: 92-20 = X1 OOYO

E5

(for all types of slide projectors).

8 Test resultsGive results of the tests according to this part of ISO 11315 in the form of the example intable 1.

Table 1- Report of tests results - Example of presentation of results for a slide projector

ITest subject Projector manufacturer / model name/ number/ serial

number

Rated voltage 100 V, 120 V, 230 V, 240 VFrequency 50 Hz or 60 H~Nominal lamp 24 V / 250W HalogenManufacturer and type MNO comp. Type No. 1234number of lampLens ( name), ~= 3,5/85 mm

Picture aperture format nominal 24 mm x 36 mmactual 22.5 mm x 34.3 mm

Voltage selector Projector input Lamp input Luminous fluxposition

v- V Hz v lm

100 100 50 22,95 710I20 120 60 23,00 720220/230 230 50 24,00 810240 240 60 23,05 730

Uniformity of screen illuminance gz.b = 75 % g2.10=68Y0 gz.zo = 62 %

7

IS 15357 [Part 1) :20031s0 11315-1 :1997

Annex A(informative)

Measuring methods

It is becoming increasingly common today to use several alternative types of projection during a

single show. This fact makes it necessary to set up a standardized technique for measuringlight on a screen for ~ projection methods, in order to reach defined projection conditionsduring a presentation with different types of projectors.

All projection methods included in this part of ISO 11315 involve optical projection, i.e. the

projection of an image onto a projection screen by optical means. Electronic projection methods

which project images onto monitor-tvp e screens (e ,g .TV monitors, TV receivers, computers,etc.) do not fall within the scope of this part of ISO 11315. Furthermore, holographic systemsare not within the scope of this part of ISO 11315.

The final purpose of each projection system is the viewing of projected images.

A projection system consists of a projector (still projector; pure optical projection or in

combination with a video system) and a reflection or transmission screen.

Independent of the projection method, fundamental uniform measuring systems for the lightcoming from the projector (going towards the screen) and for the light coming from the screen(going to the viewing area) should be applied.

Measuring methods are required for the

- screen illuminance: this part of ISO 11315, for still projection(revision of ISO 8341:1 989)

- screen luminance: ISO 11315-2, for still projectionISO 2910:1990, for motion-picture projection

- distribution of screen luminance: 1S0 11315-3 for rear projection screens,still projection

ISO 11315-4 (which is being prepared) forfront projection screens, still- and motion-picture projection

NOTE — Still motion-picture projection with change-over devices often uses two or more projectors standing nextto each other and operating alternately. The distance between the two projection lenses may be up to 1,5 m to2,0 m. A projection distance of 20 m can thus produce a horizontal projection angle of 2,5° to 3°.

8

IS 15357 (Part 1) :20031s0 11315-1 :1997

[1] ISO 1755:1987,

[2] ISO 2910:1990,

[3] ISO 7943-1:1987,

[4] ISO 7943-2:1987,

Annex B(informative)

Bibliography

Photography - Projector s/ides - Dimensions.

Cinematography - Screen luminance for the projection ofmotion-picture prints in indoor theatres and review rooms,

Photography - Overhead projectors - Part 1: Projectionstages - Dimensions.

Photography - Overhead projectors - Part 2: Transparencies andtransparency frames - Dimensions.

[5] ISO 11315-2:1997, Photography - Projection in indoor rooms - Part 2: Screen /uminancetest for still and video projection.

[6] ISO 11315-3:–1), Photography - Projection in indoor rooms - Part 3.’ Projection reflectingscreens.

[7] ISO 1131 5-4:— 1), Photography - Projection in indoor rooms - Parf 4: Reflecting projectionscreens - Classification and measurement of reflected screen luminance/eve/s and sound attenuation.

[8] CIE No. 50:1979, Proceedings at the 1979 CIE Session (Kyoto).

1) To be published.

9

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