ISO 3621:1994

INTERNATIONAL
STANDARD
Second edition
1994-12-15
Photography - Processing chemicals -
Specifications for sodium tetraborate
decahydrate
Photographie - Produits chimiques de traitement - Spkifications relatives au
tktraborate de sodium d&ahydrat&
Reference nufnber
ISO 3621:1994(E)

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ISO 3621:1994(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. Esch 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 1
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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 % sf the member bodies casting
a vote.
International Standard ISO 3621 was prepared by Technical Committee
ISOfIC 42, Photography.
This second edition cancels and replaces the first edition (ISO 3621:1976),
which has been technically revised.
0 ISO 1994
AH rights reserved. Unless otherwise specified, no part of this publication mag/ be reproduced
utilized in any form or by an)g means, electronie or mecha nical, rncluding photocopytng and
0r
mi crof ilm, wlthout permlssi on in writing from the publisher.
International Organization for Standar ,dization
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Pnnted in Switzerland

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0 ISO
Introduction
0.1 This International Standard is one of a series that establishes criteria
of purity for chemicals used in processing photographic materials. General
test methods and procedures cited in this International Standard are
compiled in Parts 1, 5 and 9 of ISO 10349.
This International Standard is intended for use by individuals with a
working knowledge of analytical techniques, which may not always be the
case. Some of the procedures utilize caustic, toxic or otherwise hazardous
chemicals. Safe laboratory practice for the handling of chemicals requires
the use of safety glasses or goggles, rubber gloves and other protective
apparel such as face masks or aprons where appropriate. Normal pre-
cautions required in the Performance of any Chemical procedure are to be
exercised at all times but care has been taken to provide warnings for
hazardous materials. Hazard warnings designated by a letter enclosed in
angle brackets, < >, are used as a reminder in those Steps detailing
handling operations and are defined in ISO 10349-1. More detailed
information regarding hazards, handling and use of these chemicals may
be available from the manufacturer.
0.2 This International Standard provides Chemical and physical require-
ments for the suitability of a photographit-grade Chemical. The tests
correlate with undesirable photographic effects. Purity requirements are
set as low as possible consistent with these photographic effects. These
criteria are considered the minimum requirements necessary to assure
sufficient purity for use in photographic processing solutions, except that if
the purity of a commonly available grade of Chemical exceeds photographic
processing requirements and if there is no economic penalty in its use, the
purity requirements have been set to take advantage of the availability of
the higher-quality material. Every effort has been made to keep the
number of requirements to a minimum. Inert impurities are limited to
amounts which will not unduly reduce the assay. All tests are performed
on samples “as received” to reflect the condition of materials furnished for
use. Although the ultimate criterion for suitability of such a Chemical is its
successful Performance in an appropriate use test, the shorter, more
economical test methods described in this International Standard are
generally adequate.
Assay procedures have been included in all cases where a satisfactory
method is available. An effective assay requirement serves not only as a
safeguard of Chemical purity but also as a valuable complement to the
identity test. Identity tests have been included whenever a possibility
exists that another Chemical or mixture of chemicals could pass the other
tests.
All requirements listed in clause 4 are mandatory. The physical appearance
of the material and any footnotes are for general information only and are
not part of the requirements.
. . .
Ill

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ISO 3621:1994(E) 0 ISO
0.3 Efforts have been made to employ tests which are capable of being
run in any normally equipped laboratory and, wherever possible, to avoid
tests which require highly specialized equipment or techniques.
Instrumental methods have been specified only as alternative methods or
alone in those cases where no other satisfactory method is available.
Over the past few years, great improvements have been made in
instrumentation for various analyses. Where such techniques have
equivalent or greater precision, they may be used in place of the tests
described in this International Standard. Correlation of such alternative
procedures with the given method is the responsibility of the User. In case
of disagreement in results, the method called for in the specification shall
prevail. Where a requirement states Yo pass test ”, however, alternative
methods shall not be used.

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INTERNATIONAL STANDARD o Iso ISO 3621:1994(E)
Processing chemicals - Specifications for
Photography -
sodium tetraborate decahydrate
ISO 10349-9: 1992, Photograph y - Photographic-
1 Scope
grade chemicals - Test methods - Part 9: Reaction
This International Standard establishes criteria for the
to ammoniacal silver nitra te.
purity of photographit-grade sodium tetraborate deca-
hydrate and specifies the tests to be used to deter-
mine the purity.
3 General
3.1 Physical proper-Ges
2 Normative references
Sodium tetraborate decahydrate, Na2B407.1 OH*O,
exists as either a white crystalline powder or
The following Standards contain provisions which,
granules. lt has a relative molecular mass of 381,37.
through reference in this text, constitute provisions of
this International Standard. At the time of publication,
the editions indicated were valid. All Standards are
3.2 Hazardous properties
subject to revision, and Parties to agreements based
on this International Standard are encouraged to
Sodium tetraborate decahydrate is not hazardous
investigate the possib
...