ISO 3623:1994

INTERNATIONAL
ISO
STANDARD
3623
Second edition
1994-12-15
Photography - Processing chemicals -
Specifications for anhydrous potassium
carbonate
Photographie - Produkts chimiques de traitement - Spkifications pour Ie
carbona te de po tassium anh ydre
Reference number
ISO 3623:1994( E)

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ISO 3623: 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
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 % of the member bodies casting
a vote.
International Standard ISO 3623 was prepared by Technical Committee
lSO/TX 42, Photography.
This second edition cancels and replaces the first edition (ISO 3623:1976),
which has been technically revised.
Annex A of this International Standard is for information only.
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organi zation for Standardization
Case postale 56 l CH-l 2 11 Geneve 20 l Switzerland
Printed in Switzerland

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ISO 3623:1994(E)
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, 6, 7, 8 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.
8.2 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 3623: 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 “to pass test ”, however, alternative
methods shall not be used.

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ISO 3623: 1994(E)
INTERNATIONAL STANDARD o ISO
- Specifications for
Photography - Processing chemicals
anhydrous potassium carbonate
3 General
1 Scope
3.1 Physical properties
This International Standard establishes criteria for the
purity of photographit-grade anhydrous potassium
Anhydrous potassium carbonate, K2COs, exists in the
carbonate and specifies the tests to be used to
form of colourless white granules or powder. lt has a
determine the purity.
relative molecular mass of 138,Zl.
3.2 Hazardous properties
2 Normative references
Potassium carbonate is irratating to the eyes, skin and
throat.
The following Standards contain provisions which,
through reference in this text, constitute provisions of
3.3 Storage
this International Standard. At the time of publication,
the editions indicated were valid. All Standards are
Potassium carbonate should be stored in a closed
subject to revision, and Parties to agreements based
Container at room temperature.
on this International Standard are encouraged to
investigate the possibility of applying the most recent
4 Requirements
editions of the Standards indicated below. Members
of IEC and ISO maintain registers of currently valid
A summary of the requirements is shown in table 1.
International Standards.
ISO 10349-1: 1992, Photography - Photographic-
5 Reagents and glassware
grade chemicals - Test methods - Part 1: General.
All reagents, materials and glassware shall conform to
the requirements specified in ISO 10349-1 unless
ISO 10349-5: 1992, Photography - Photographic-
otherwise noted. The hazard warning Symbols used
grade chemicals - Test methods - Part 5: Determi-
as a reminder in those Steps detailing handling oper-
nation of heavy metals and iron content.
ations are defined in ISO 10349-1. These Symbols are
used to provide information to the user and are not
ISO 10349-6: 1992, Photography - Photographic-
meant to provide conformance with hazardous
grade chemicals - Test methods - Part 6: Determi-
labelling requirements as these vary from country to
nation o f halide con tent.
country.
ISO 10349-7: 1992, Photography - Photographic-
6 Sampling
grade chemicals - Test methods - Part 7: Determi-
nation of alkalinity or acidity.
See ISO 10349-1.
ISO 10349-8: 1992, Photography - Photographic-
7 Test methods
grade chemicals - Test methods - Part 8: Determi-
na tion of volatile matter.
7.1 Assay
ISO 10349-9: 1992, Photography - Photographic-
7.1.1 Specification
grade chemicals - Test methods - Part 9: Determi-
Content of K2C03 shall be 97,0 % (HZ/LV) min.
nation of reaction to ammoniacal silver nitrate.

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ISO 3623: 1994(E) 0 ISO
Table 1 - Summary of requirements
International Standard in
Test Limit Subclause
which test method is given
Assay (as K2C0s) 97,0 % (m/m) min. 7.1 ISO 3623
Heavy metals (as Pb) 0,001 % (m/m) max. 7.2 ISO 10349-5
Iran (Fe) 0,001 % (m/m) max. 7.3 ISO 10349-5
Halides (as Cl-) 0,l % (&Tz) max. 7.4 ISO 10349-6
Volatile matter at 150 “C 2,0 % (m/m) max. ISO 10349-8
7,5
Reaction to ammoniacal silver nitrate To pass test 7.6 ISO 10349-9
Free alkali (as KOH) 1,O % (m/m) max. 7.7 ISO 3623
0,4 % (m/m) max. 7.8 ISO 3623
Bicarbonate (as KHCOs)
Calcium and magnesium (as Mg) 0,015 % (HZ/VZ) max. 7.9 ISO 3623
Appearance of Solution Clear and free from insoluble matter 7.10 ISO 3623
except for a slight flocculence
NOTE - m/m = mass/mass
7.12 Reagents m is the mass, in grams, of the test Portion;
6,91 is the conversion factor obtained from the
7.121 Hydrochlorit acid, HCI, Standard volumetric
mass of potassium carbonate equivalent to
Solution of 1,OO mol/1 l) *).
1 mole of hydrochloric acid (i.e. 138,2/2) x
the conversion factor for millilitres to litres
7.1.2.2 Methyl orange indicator, 0,4 g/l.
(i.e. 0,001) x 100 (for percentage).
7.1.3 Apparatus
7.2 Heavy metals content
7.1.3.1 Burette, of 50 ml capacity.
72.1 Specification
7.1.4 Procedure
Maximum content of heavy metals shall be
0,001 % (mlm).
Weigh, to the nearest 0,001 g, a test Portion of about
2,5 g and dissolve it in 50 ml of water. Add two drops
7.2.2 Procedure
of the methyl orange indicator (7.1.2.2) and titrate
NOTE 1 The Standard for the iron test (7.3) is prepared in
(7.1.2.1) to the endpoint
with the hydrochloric acid
the same way as the heavy metals Standard.
when the colour changes from yellow to red.
Determine the percentage of heavy metals in accord-
ante with ISO 10349-5. Use a test Portion of 4,90 g to
7.15 Expression of results
5,lO g prepared in accordance with ISO 10349-5:
1992, 7.3. Use 5 ml of the heavy metals Standard
The assay, expressed as a percentage by mass, for
prepared in accordance with ISO 10349-5:1992, 8.1.2.
K2C03, is given by
6,91 -em Vlm
7.3 Iron content
where
7.3.1 Specification
c is the act
...