SIST EN 60735:1999

SLOVENSKI STANDARD
SIST EN 60735:1999
01-julij-1999
Measuring methods for video tape properties (IEC 60735:1991)
Measuring methods for video tape properties
Meßverfahren für die Eigenschaften von Video-Magnetbändern
Méthodes de mesure des propriétés des bandes magnétiques pour magnétoscopes
Ta slovenski standard je istoveten z: EN 60735:1991
ICS:
33.160.40 Video sistemi Video systems
SIST EN 60735:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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NORME CEI
IEC
INTERNATIONALE
735
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1991-09
Méthodes de mesure des propriétés
des bandes magnétiques pour magnétoscopes
Measuring methods for video tape properties
Copyright - all rights reserved
© IEC 1991 Droits de reproduction réservés —
publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
Aucune partie de cette
forme que ce soit et par aucun any form or by any means, electronic or mechanical,
utilisée sous quelque
y compris la photo- including photocopying and microfilm, without permission in
procédé, électronique ou mécanique,
de l'éditeur. writing from the publisher.
copie et les microfilms, sans l'accord écrit
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For price, see current catalogue

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735©IEC - 3 -
CONTENTS
Page
FOREWORD 5
Clause
1 Scope 7
2 Normative references 7
3 Testing environment 7
4 Mechanical properties 7
4.1 Tape width 7
4.2 Tape thickness 9
4.3 Tensile tests 9
4.4 Residual elongation 9
4.5 Longitudinal shrinkage 9
4.6 Coefficient of elongation in humidity 9
11
4.7 Transverse cupping
11
4.8 Longitudinal curvature
11
4.9 Coefficient of friction
4.10 Layer-to-layer adhesion 13
4.11 Video head wear 15
5 Electromagnetic and electrical properties 15
5.1 Coercivity H 15
and retentivity Br
5.2 Coating resistance 15
6 Tape properties measured on a video tape recorder 15
6.1 Video properties 15
6.2 Audio properties 21

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735©IEC - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MEASURING METHODS
FOR VIDEO TAPE PROPERTIES
FOREWORD
1) The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use and they are accepted by the National
2)
Committees in that sense.
3) In order to promote international unification, the IEC expresses the wish that all National Committees
should adopt the text of the IEC recommendation for their national rules in so far as national conditions will
permit. Any divergence between the IEC recommendation and the corresponding national rules should, as
far as possible, be clearly indicated in the latter.
This International Standard has been prepared by Sub-Committee 60B: Video recording,
of IEC Technical Committee No. 60: Recording.
This second edition of IEC 735 replaces the first edition, issued in 1982.
The text of this standard is based on the following documents:
DIS Report on Voting
60B(CO)124 60B(CO)136
Full information on the voting for the approval of this standard can be found in the Voting
Report
indicated in the above table.

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735©IEC - 7 -
MEASURING METHODS
FOR VIDEO TAPE PROPERTIES
1 Scope
This standard describes the measuring methods for evaluation of the properties of
magnetic tapes used for video recorders.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the editions indicated
rties to agreements based on this
were valid. All standards are subject to revision, and pa
International Standard are encouraged to investigate the possibility of applying the most
ISO maintain regis-
recent editions of the standards indicated below. Members of IEC and
ters of currently valid International Standards.
IEC 698: 1981, Measuring methods for television tape machines.
IEC 883: 1987, Measuring method for chrominance signal-to-random noise ratio for video
tape recorders.
IEC 1105: 1991, Reference tapes for video tape recorder systems (being printed).
ISO 468: 1982, Surface roughness - Parameters, their values and general rules for speci-
fying requirements.
ISO/R 527: 1966, Plastics, Determination of tensile properties.
CCIR Recommendation 567-2 - Recommendations and reports of the CCIR (1986) -
Volume XII - Transmission of sound broadcasting and television signals over long
distances (CMTT).
3 Testing environment
All properties, if not otherwise specified, shall be measured at a temperature of
20 °C ± 1 °C at a humidity of 48 % to 52 % and an atmospheric pressure between 86 kPa
and 106 kPa. The test sample to be measured shall be stored for 24 h in the above
conditions to ensure correct testing results. This is defined as the standard environment
for this standard.
4 Mechanical properties
4.1 Tape width
The tape, covered with a glass plate, shall be measured without tension at a minimum of
five different positions along the tape using a calibrated microscope or profile projector
having an accuracy better than 2 prn. The tape width shall be defined as the average of
the five readings.

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735©IEC - 9 -
4.2 Tape thickness
The tape thickness shall be obtained by using five samples from the beginning and five
from the end of the tape, placing these ten sections on top of each other in a suitable
manner, measuring with a micrometer gauge and dividing the reading by ten.
4.3 Tensile tests
The measurements are made in accordance with ISO/R 527. The length of the test sample
shall be 200 mm. The rate of elongation for all tensile tests shall be 100 mm/min
(ISO/R 527, rate D).
4.3.1 Breaking strength
The sample shall be loaded until the breaking point of the sample shall be reached. The
force at that point shall be defined as the breaking strength of the tape.
4.3.2 Yield strength (F 5 %)
The yield strength (F 5 %) shall be defined as the force necessary to produce 5 % elonga-
tion of the tape.
4.4 Residual elongation
To measure the residual elongation, a test sample of approximately 1 m shall be subjected
to a tension of 50 N/mm2 total cross-section for a period of 3 min.
The sample shall then be measured with negligible force (0,25 N) 3 min after the load has
been removed.
The residual elongation shall be stated as a percentage of the original tape length.
4.5 Longitudinal shrinkage
A test sample (approximately 1 m) shall be stored in the standard environment for 48 h. It
shall then be vertically suspended and loaded with 0,25 N. The length of the test sample,
3 min after the load has been applied, shall be defined as the original tape length.
The environment shall be then changed to 50 °C and 13 % relative humidity for a period of
18 h. Three hours after restoring the standard environment, the shrinkage of the sample
shall be measured and expressed as a percentage of the original tape length.
4.6 Coefficient of elongation in humidity
A test sample (approximately 1 m) shall be stored in the standard environment for 48 h. It
shall then be vertically suspended and loaded with 0,25 N. The length of the test sample,
3 min after the load has been applied, shall be defined as the original tape length.

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735 ©IEC - 11 -
After increasing the relative humidity by 30 % for a period of 18 h the elongation shall be
measured and expressed as a percentage of the original tape length.
Transverse cupping
4.7
A tape sample of 10 mm length shall be placed, concave side down, on a smooth flat
surface. Transverse cupping shall be the maximum departure of the tape sample from the
ace. The time between cutting the tape and the measurement shall be at least 1 h.
flat surf
The tape sample and the test su rface shall not be charged electrostatically.
4.8 Longitudinal curvature
4.8.1 Static longitudinal curvature
A tape sample of 1 m shall be allowed to unroll and assume its natural curvature on a flat
ace. The maximum deviation of the edge of the tape from a straight line joining the
surf
extremities of the tape sample shall be defined as the static longitudinal curvature.
Dynamic measuring of longitudinal curvature
4.8.2
The test sample shall be measured in a test arrangement according to figures 1 a and 1 b.
The variation of the tape edge shall be measured with a light sensor through a slot of
1 mm width, in the area of the lower tape edge. The outpout signal shall be proportional to
the variations of the tape edge. The variation of each edge shall be measured and the
worst value shall be reported.
4.9 Coefficient of friction
4.9.1
Quasi-static friction of the coating side
A test drum shall be used, this being a stainless steel cylinder (figure 2) with a diameter of
100 mm and a surface roughness Ra = 0,25 pm in accordance with ISO 468. For particular
applications, a drum of different material and different su rface roughness may be used.
The drum shall be cleaned with a solvent which leaves no residuals on the su rface before
starting the procedure.
Procedure: with a velocity of 5 cm/min the test sample with its coating side facing the test
drum shall be pulled over the drum for 2 min. After a sho rt pause the procedure can be
started under the same conditions and the results recorded.
1 F2
Coefficient of friction p = — x In
F1
a
where:
a is the angle of wrap around the drum (it) in radians
F1
= 0,5 N Toad
F2 = F1 + friction.
(Values of velocity and load are chosen for practical reasons).

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735 ©IEC - 13 -
4.9.2 Quasi-static friction of the reverse side
The drum shall be replaced by a stainless steel pin of 8 mm diameter and a su rface
roughness Ra = 0,07 pm. For particular applications, a pin of different material and
different surface roughness may be used. The test procedure is as detailed in 4.9.1 except
that the reverse side of the tape is facing the pin surface.
4.9.3 Dynamic friction of the coating side
The dynamic friction shall be measured with the equipment shown in figure 3. This
machine is capable of varying the speed in the range from 0.5 cm/s to about 20 cm/s. For
material of drum and pin, see 4.9.1 and 4.9.2.
When a tape is run from 0,5 cm/s to about 20 cm/s, the maximum value of p and the
speed at which the maximum value is obtained shall be noted.
From the friction versus speed curve, the coefficient of friction shall be calculated at two
F2 is at a maximum and at a specified speed,
speed values, namely at the speed at which
characteristic for the recording equipment.
The frictional characteristics can be expressed by various values:
a) maximum value of friction and its speed;
b) at a certain speed to be specified.
4.9.4 Dynamic friction of the reverse side
For measurement on the reverse side, the test procedure is the same as in 4.9.3, except
that the reverse side is facing the pin.
4.10 Layer-to-layer adhesion
A tape of 1 m in length shall be wound on a glass tube of 36 mm diameter at a tension of
5 N/mm2 with one end of the tape fixed to the glass tube.
The wound test piece shall be kept at a temperature of 45 °C ± 3 °C and relative humidity
of 80 % for 4 h, and afterwards under the standard environment for 24 h.
For some special applications requiring more stringent test conditions, the tape sample
is wound on a 12,7 mm diameter tube of non-oxidizing material and exposed to a
temperature of 54 °C and relative humidity of 84 % for 16 h and afterwards to the standard
environment for 24 h.
Finally, the test piece shall be unwound slowly with a 0,1 N load at the end. Then any
tendency of tape sticking and delamination of magnetic coating shall be observed.

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735 © IEC
4.11 Video head wear
Tape tension, head mounting, pole tip protrusion
...