ISO 17121:2000
(Main)Cinematography — Work stations used for film and video production — Requirements for visual and audio conditions
Cinematography — Work stations used for film and video production — Requirements for visual and audio conditions
Cinématographie — Stations de travail utilisées en production de film et vidéo — Prescriptions pour les conditions visuelles et audio
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 17121
First edition
2000-10-15
Cinematography — Work stations used for
film and video production — Requirements
for visual and audio conditions
Cinématographie — Stations de travail utilisées en production de film et
vidéo — Prescriptions pour les conditions visuelles et audio
Reference number
ISO 17121:2000(E)
©
ISO 2000
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ISO 17121:2000(E)
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ISO 17121:2000(E)
Contents
Foreword.iv
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Requirements .4
4.1 Arrangements of picture monitors and data monitors at work stations.4
4.1.1 Viewing distances.4
4.1.2 Range of vision .5
4.1.3 Arrangement of picture monitors.8
4.1.4 Arrangement of data monitors .10
4.2 Spatial arrangement and design .10
4.2.1 Viewing geometry .10
4.3 Viewing conditions .13
4.3.1 General.13
4.3.2 Luminance of the television screen.13
4.3.3 Lighting of the viewing room.13
4.3.4 Script lighting and console lighting.14
4.3.5 Colour of room .14
4.3.6 Reflections.14
4.3.7 Screen environment .14
4.3.8 Vibration levels .14
4.4 Picture monitors .15
4.5 Acoustic conditions.15
4.5.1 General.15
4.5.2 Recommended maximum permitted sound pressure level of continuous background noise .15
4.5.3 Required airborne sound isolation between rooms.16
4.5.4 Architectural acoustics with regard to buildings.16
4.5.5 Room acoustics .18
4.5.6 Sound monitors .18
4.6 Acceptance.20
5 Marking .20
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ISO 17121:2000(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 17121 was prepared by Technical Committee ISO/TC 36, Cinematography.
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INTERNATIONAL STANDARD ISO 17121:2000(E)
Cinematography — Work stations used for film and video
production — Requirements for visual and audio conditions
1 Scope
This International Standard specifies the requirements for work stations used for electronic image and sound
production in film and video facilities and broadcasting organizations. It provides assistance in achieving a consistent
and critical evaluation of television and video programme material with a view to facilitating programme exchange in
commonly used review conditions.
This International Standard is not applicable to work stations based on general purpose office computers or film
production by traditional methods.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
CIE 15.2:1986, Colorimetry.
CIE S005:1998, CIE standard illuminant for colorimetry.
EBU Specifications Techn. 3213:1975, EBU standard of chromaticity tolerances of studio monitors.
EBU Specifications Techn. 3263:1991, Specification of grade-1 colour picture monitors.
EBU-Recommendation R 23:1987, Procedure for the operational alignment of grade-1 colour picture monitors.
ITU-Report 624-4/90:1990, Recommendations and Reports of the CCIR — Characteristics of television systems.
ITU-Recommendation 500, volume XI:1974, Recommendations and Reports of CCIR — Method for the subjective
assessment of quality of television pictures.
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
eye point term
point in space where the eyes of the user of a particular item of technical equipment are positioned
NOTE 1 It is dependent on the body dimensions of the user and the posture he or she adopts.
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ISO 17121:2000(E)
NOTE 2 The technical equipment referred to in this case is a picture monitor or a data monitor.
3.2
viewing angle
angle between the line of sight and the surface normal of the object of vision
3.3
image resolution
capacity of the screen to display dots or lines separately
3.4
height of picture
electronic image measured vertically
3.5
picture monitor
device for the reproduction and visual assessment of electronic images
3.6
binocular vision
sight with both eyes
3.7
field of fixation
sum total of the object points which can be fixed with the head at rest, moving only the eyes
3.8
data monitor
device for displaying alphanumeric characters and graphic representations
3.9
electronic image
television picture produced by the technical processing of film, video, text and graphics in accordance with
ITU-Report 624-4/90
3.10
detect
notice that one or more optical stimuli exist
3.11
recognize
determine what is seen through congruence being established between the object of vision and its remembered
meaning
3.12
space of recognition
space delimited by all the eye points from which all the characters displayed on a surface can be recognized with
certainty
NOTE 1 The extent of the space of recognition is dependent on the viewing distance, the viewing angle and the size of the
characters being looked at.
NOTE 2 A data monitor is an example of the type of surface referred to in this definition.
3.13
fixation
look
directing the eyes at a point
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ISO 17121:2000(E)
NOTE 1 A normal-sighted eye assumed, the adjustment takes place in such a way that an image of the fixed point is formed
in the middle of the fovea.
NOTE 2 Fixation is the prerequisite for the recognition of objects of vision.
3.14
surface normal
perpendicular onto the surface of the display (here, the screen)
3.15
control desk
operating console or work table with work equipment, for example keys, controls or measuring equipment, for
controlling and processing of picture and/or sound
3.16
monitor wall
several picture monitors arranged next to each other vertically and/or horizontally
3.17
monocular vision
sight with one eye
3.18
near point
point to which the eye is adjusted at the highest dioptric power of its optical system
3.19
viewing distance
distance between the eye and the object of vision
NOTE Unless indicated otherwise, the viewing distance is based on the centre of the screen.
3.20
line of sight
straight line between the centrally-imaged object point and its image point
NOTE This line goes approximately through the two nodal points of the eye.
3.21
field of vision
field of fixation and visual field
3.22
object of vision
object in external space, the image of which on the retina leads to a perception
NOTE Objects of vision are electronic images on picture monitors and characters on data monitors.
3.23
visual angle
angle whose vertex is at the eye and whose angle sides encompass the object of vision
SeeFigure2.
NOTE Unless indicated otherwise, the visual angle is based on the height of the object of vision.
3.24
peak luminance
luminance adjusted on a monitor that corresponds to the white level of the picture signal
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ISO 17121:2000(E)
3.25
sound monitors
device (loudspeaker) for reproducing sound signals
3.26
extended field of fixation
space delimited by sum total of all object points that can be fixed with the body at rest, only moving the head and
eyes
4 Requirements
4.1 Arrangements of picture monitors and data monitors at work stations
4.1.1 Viewing distances
4.1.1.1 General
When specifying viewing distances, determine the nature of the task in hand; for example, distinguish between
assessing television images on picture monitors and reading text on data monitors.
The specifications assume viewers to have normal sight, in particular for colour television. Defective vision shall be
corrected by aids to vision such as spectacles.
4.1.1.2 Viewing distances for picture monitors
1)
This International Standard is based on television images in accordance with ITU (previously CCIR)-Report 624-
4/90.
The viewing distance for picture monitors is specified as a multiple of the visible height of the picture h (millimetres)
B
(see ITU Recommendation 500, volume XI, 1974).
The viewing distance as shown in Table 1 may vary depending on the nature of the task.
Table 1 — Viewing distances
a
Task requirements
Viewing distance
suitable for quality assessment and for reliably
from 4 h to 6�h
B B
correcting details of pictures
from 6 h to 9�h suitable for assessing and checking whole
B B
pictures
from 9 h to 14�h suitable for rough assessments
B B
unsuitable for assessment; however, the picture
from 14 h to 20�h
B B
content is still clearly recognizable for checking
purposes
a
For observing HDTV (high definition television) images, the distances given may be halved.
1) International Telecommunication Union.
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ISO 17121:2000(E)
4.1.1.3 Viewing distances for data monitors
The viewing distance for data monitors shall be selected so that individual characters and symbols on the screen are
recognized from the position of the eye point. This is assured when the height of the character without ascenders or
descenders, for example capital letters, appears at a viewing distance of 500 mm from a visual angle of at least
20 angular minutes (see Figures 1 and 2).
Viewing distances of less than 200 mm shall be avoided because this is less than the position of the near point.
For a viewing distance of 500 mm, the character height shall be at least 2,9 mm.
For viewing distances of more than 500 mm, a visual angle of 20 angular minutes is indicated if the height of the
character corresponds to the actual viewing distance, divided by 170.
Figure 1 — Viewing distance l, and viewing angle�, displayed in the centre of the screen
Figure 2 — Viewing angle�
4.1.2 Range of vision
4.1.2.1 General
The characteristics of the range of vision (lines of sight, fields of vision) and the sitting posture, based largely on the
work station, are the key factors for the arrangement of picture monitors and data monitors.
The figures indicated (dimensions and angles) represent general ergonomic basic principles for the anthropometric
design of work stations.
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ISO 17121:2000(E)
4.1.2.2 Lines of sight
The course of the lines of sight forms the reference for the object of vision (for example television images, characters
on data monitors, keys on the control desk) and, in conjunction with the fields of vision, is important for the
arrangement of the work equipment.
In order to achieve optimum, that is large, visual angles, the lines of sight of the eye should correspond to the surface
normal.
When the lines of sight are horizontal, the head is held up and the eyes are looking straight ahead; the line of sight
is thus identical to the horizontal [see Figure 3a)].
With a head-related line of sight, the head is held in a relaxed position (the head axis inclined forward with respect
to the trunk axis by 10� to 15�) and the eyes are looking straight ahead; the lines of sight are inclined by 10� to 15�
with respect to the horizontal [see Figure 3b)].
With a normal line of sight, the eyes and head are in a relaxed position; the line of sight is inclined downwards by
25� to 35� with respect to the horizontal [see Figure 3c)].
a) Horizontal line of sight b) Head-related line of sight c) Normal line of sight
Key
1 Horizontal line of sight
2 Head-related line of sight
3 Normal line of sight
4 Horizontal (0��
Figure 3 — Angle of inclination of the lines of sight
4.1.2.3 Fields of vision
A distinction is made between monocular and binocular fields.
In the following cases, binocular fields are assumed:
� the fields of vision are distinguished according to optimum extent and maximum extent, whereby it is
preferable to have the display in the optimum field;
� the fields have different vertical and horizontal extents.
All the visual stimuli that can be simultaneously detected, with the eyes and the head at rest, lie in the visual field.
Inthevisualfieldoutsideafieldlessthan1� around the fixation point, none of the objects looked at are recognized; all
that is perceived are differences in luminance and colour.
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ISO 17121:2000(E)
The dimensions of the useful visual field depend on the characteristics of the visual stimulus (size, luminance, colour
and temporal characteristics, for example blinking) and on the average luminance in the visual field.
Fatigue, psychic distraction and stress can reduce the visual field (see Figure 4).
The visual field of fixation is attained by enveloping all fixable points within the field of fixation by the visual field. It is
thus the sum of all visual fields with the head at rest and moving (fixing) eyes (see Figure 5).
The extended visual field encompasses the area of all visual fields that come into being through movement of the
head and eyes.
NOTE For definition of field of vision, see 3.21.
Key
1 Left eye
2 Binocular
3 Right eye
Figure 4 — Visual field for light stimuli
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ISO 17121:2000(E)
Key
1 Visual field of vision
2 Visual field
3 Objects at the limit of the field of fixation: centrepoint of the visual field
4 Field of fixation
Figure 5 — Visual field of fixation
4.1.3 Arrangement of picture monitors
Set up the picture monitors taking into consideration the viewing distances in accordance with 4.1.1 and the fields of
vision in accordance with 4.1.2.3. Arrange them so that there is no straining of the neck muscles while viewing, no
strained body posture and no strain to the eyes.
The visual fields indicated in Figure 6 are based on the normal line of sight. If the visual task necessitates the head
being held up, for example with a monitor wall, then the normal line of sight around the eye point shall be inclined
upwards by 10� to 15�.
Arrange picture monitors that are viewed simultaneously in the optimum useful visual field A, in accordance with
Figure 6. Arrange picture monitors for quality assessment of television images and for correcting image details in the
angles given under visual field A.
Set up picture monitors that are frequently viewed from the operating board in the optimum useful visual field of
fixation B, in accordance with Figure 6.
Picture monitors that only serve informative purposes and are only observed from time to time may be arranged in the
extended visual field C, in accordance with Figure 6.
If they are arranged 15� above the horizontal line
...
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