ISO 7832:2014
(Main)Cinematography — Photoelectric output factor of photographic-type audio-level test films — Measurement and calibration
Cinematography — Photoelectric output factor of photographic-type audio-level test films — Measurement and calibration
ISO 7832:2014 specifies a method of measuring and calibrating the photoelectric output factor of single channel analogue photographic-type audio-level test films in all gauges, using a calibrating sound reproducer. It is applicable to both variable area- and variable density-type sound records with a silver audio track. It also specifies the performance of a calibrating audio reproducer.
Cinématographie — Facteur de sortie photoélectrique des films d'essai de niveau sonore de type optique — Mesurage et étalonnage
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 7832
Second edition
2014-10-01
Cinematography — Photoelectric
output factor of photographic-type
audio-level test films — Measurement
and calibration
Cinématographie — Facteur de sortie photoélectrique des films
d’essai de niveau sonore de type optique — Mesurage et étalonnage
Reference number
ISO 7832:2014(E)
©
ISO 2014
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ISO 7832:2014(E)
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ii © ISO 2014 – All rights reserved
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ISO 7832:2014(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and symbols . 1
4 Method of measurement . 2
5 Method of calibration . 2
5.1 DC method . 2
5.2 AC method . 2
6 Calibration procedure . 2
7 Calibrating reproducer . 2
Annex A (normative) DC and AC calibration . 6
© ISO 2014 – All rights reserved iii
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ISO 7832:2014(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 36, Cinematography.
This second edition cancels and replaces the first edition (ISO 7832:1987), of which it constitutes a
minor revision.
iv © ISO 2014 – All rights reserved
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INTERNATIONAL STANDARD ISO 7832:2014(E)
Cinematography — Photoelectric output factor of
photographic-type audio-level test films — Measurement
and calibration
1 Scope
This International Standard specifies a method of measuring and calibrating the photoelectric output
factor of single channel analogue photographic-type audio-level test films in all gauges, using a calibrating
sound reproducer. It is applicable to both variable area- and variable density-type sound records with a
silver audio track.
It also specifies the performance of a calibrating audio reproducer.
Calibrated audio-level test films are employed to measure the precise output level of photographic sound
reproducers and the photoelectric output factor of different sound records. They are also employed
to establish a reference level on a standard program level meter, should that be appropriate for the
installation in use.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 2939, Cinematography — Picture image area on 35 mm motion-picture release prints — Position and
dimensions
ISO 4243, Cinematography — Picture image area and photographic sound record on 16 mm motion-picture
release prints — Positions and dimensions
ISO 6025, Cinematography — Analogue photographic sound test films, 35 mm and 16 mm — Specifications
3 Terms, definitions, and symbols
For the purposes of this document, the following terms and definitions apply.
3.1
voltage outputs
V, V, V, V
1 2 3 4
output voltage levels from the calibrating sound reproducer, measured at a point in the circuitry where
the voltage relationship to the amplitude of the sound record is essentially linear
3.2
maximum photoelectric output
MPO
voltage difference obtained between full illumination of the photoelectric receptor by the scanning
beam and complete occulting of the scanning beam, as defined by V and V in Figures 1 and 2
1 4
3.3
peak-to-peak voltage
PV
voltage difference observed for a sound level test film between the maximum output at the crest of a sine
wave (+ peak) and the minimum output at the trough of a sine wave (−peak), as defined by V and V in
2 3
Figures 1 and 2
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ISO 7832:2014(E)
3.4
photoelectric output factor
POF
ratio of the PV from the film, as defined in 3.3, to the maximum output of the reproducer when reproducing
an audio level test film on a calibrating reproducer, as defined in 3.2
Note 1 to entry: An ideal test film would have a photoelectric output factor of 1,0 which is a theoretical value
that cannot be obtained in photographic sound recording due to sound track image density, base density, and fog
density.
4 Method of measurement
4.1 The photoelectric output factor shall be measured on a calibrating reproducer, as described in
Clause 7, with the required instrumentation arranged in accordance with Annex A and Figures 3 and 4.
4.2 The signal frequencies of the test film shall be as specified in ISO
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