ISO/FDIS 787-9

• Abstract:

  This document specifies a general method of test for determining the pH value of an aqueous suspension of a sample of pigment or extender.

• Status: Not Published
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: ISO/TC 256 - Pigments, dyestuffs and extenders
• Drafting Committee: ISO/TC 256/WG 3 - General test methods for colorants and extenders
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 22-Oct-2026
• Completion Date: 22-Oct-2026

• Consolidates: FprEN ISO 787-9 - General methods of test for pigments and extenders - Part 9: Determination of pH value of an aqueous suspension (ISO/FDIS 787-9:2026)
• Effective Date: 12-Feb-2026
• Revises: ISO 787-9:2019 - General methods of test for pigments and extenders — Part 9: Determination of pH value of an aqueous suspension
• Effective Date: 07-Jan-2025

ISO/FDIS 787-9 is an ISO document for the pigments and extenders field. It specifies a general laboratory method for determining the pH value of an aqueous suspension made from a sample of pigment or extender, so users can compare materials on a common test basis.

What does ISO/FDIS 787-9 specify?

ISO/FDIS 787-9 specifies a test method for measuring the pH value of an aqueous suspension of a pigment or extender sample. The document is organized as a laboratory procedure, from reagents and apparatus through sampling, testing, result expression, and reporting.

The contents are arranged in these main clauses: Scope, Normative references, Terms and definitions, Reagents, Apparatus, Sampling, Procedure, Expression of results, and Test report. That structure makes it straightforward to follow in the lab and to check whether a reported result was obtained by the specified method.

What are the key requirements of ISO/FDIS 787-9?

ISO/FDIS 787-9 focuses on preparing a controlled suspension, measuring its pH, and recording the conditions that can affect the result. The method matters in practice because pH can shift with water quality, dispersion method, and temperature, so the document fixes those points.

Sampling and reagents

• Clause 6 requires a representative sample taken in accordance with ISO 15528. In practice, the result is only useful if the sample reflects the product lot.
• Clause 4 specifies distilled or demineralized water of at least grade 3 to ISO 3696, with pH between 5,0 and 7,5, and protected from the atmosphere. This limits carbon dioxide pickup and helps avoid a shifted reading.
• Clause 4 also allows an ion intensity regulating solution, prepared as 0,1 % KCl, and says its preparation is optional but recommended. This helps make measurements more consistent across samples.
• Clause 4 adds a wetting agent for products that do not disperse easily. Ethanol, methanol, or isopropanol may be used, but the minimum amount should be used and its neutrality checked by a blank determination.

Apparatus and measurement

• Clause 5 requires a chemically resistant glass container with a suitable stopper, cleaned and rinsed before each use. This reduces contamination between tests.
• Clause 5 requires a pH measuring device capable of reading to 0,1 unit and calibrated with buffer solutions at the test temperature. That gives a measurement resolution suitable for reporting.
• Clause 5 also requires a balance with an appropriate limit of error. The mass you weigh controls the suspension concentration.

Procedure and reporting

• Clause 7 calls for the test at room temperature and a suspension concentration of 5 % to 10 % by mass. The sample is shaken, rolled, or stirred vigorously, then left for 5 min before measuring the pH.
• Clause 7 permits filtration before measurement and requires the suspension temperature to be recorded to the nearest 1 °C. It also requires the type and quantity of wetting agent to be stated when one is used.
• Clauses 8 and 9 require the result to be reported to the nearest 0,1 pH unit, together with the product identification, the document reference, the suspension concentration, the liquid used, any filtering method, deviations, anomalies, and the test date.

What terms does ISO/FDIS 787-9 define?

ISO/FDIS 787-9 uses the terms and definitions from ISO 18451-1, and several terms are central to the method.

• Aqueous suspension - The sample dispersed in water, or in the ion intensity regulating solution, for pH measurement.
• pH value - The measured acidity or alkalinity of the suspension, reported to 0,1 unit.
• Representative sample - A sample taken so it reflects the product being tested.
• Wetting agent - A liquid such as ethanol, methanol, or isopropanol used to help products disperse in water.
• Ion intensity regulating solution - A 0,1 % KCl solution used to control ionic conditions during the measurement.
• pH measuring device - The instrument used to determine the pH of the suspension after calibration.
• Pigment - A material covered by this part of ISO 787 and tested by the procedure.
• Extender - A material covered by this part of ISO 787 and tested by the procedure.

Who uses ISO/FDIS 787-9?

ISO/FDIS 787-9 is used by laboratories and technical staff working with pigments and extenders, especially in quality control and product comparison. It is relevant to manufacturers, incoming inspection teams, and test laboratories that need a repeatable pH measurement for raw materials or finished powders.

It is also useful to quality managers and buyers who compare supplier data, because the report format captures the suspension conditions, liquid used, wetting agent, and test temperature. Those details help judge whether two results are comparable.

What changed in ISO/FDIS 787-9 from the previous edition?

ISO/FDIS 787-9 is the third edition and cancels and replaces ISO 787-9:2019. The foreword states that it has been technically revised.

The stated changes are:

• the normative references have been updated;
• the specification of distilled or demineralized water in 4.1 has been changed;
• “buffer solution” in 4.2 has been changed to “ion intensity regulating solution”;
• a new 4.3, “Wetting agent”, has been added;
• the quantity of added wetting agent in Clause 7 has been changed;
• the information required in the test report in Clause 9 has been updated.

Which standards are used with ISO/FDIS 787-9?

ISO/FDIS 787-9 cites these normative references:

• ISO 3696 - Specifies the water quality used for the water in Clause 4.
• ISO 15528 - Provides the sampling method used in Clause 6.
• ISO 18451-1 - Supplies the terms and definitions used in Clause 3.

What does the ISO/FDIS 787-9 document contain?

ISO/FDIS 787-9 contains a step-by-step laboratory method, not a performance classification or product specification. It gives the reagent requirements, apparatus, sampling instruction, and the exact sequence for preparing and measuring the suspension.

The document also tells the user when a wetting agent may be needed, how to treat it, and what to record if filtration is used. In practice, that supports routine testing, incoming material checks, and reporting of pH values in a way that other users can repeat and review.

FINAL DRAFT
International
Standard
ISO/TC 256
General methods of test for
Secretariat: DIN
pigments and extenders —
Voting begins on:
2026-10-22
Part 9:
Determination of pH value of an
Voting terminates on:
2026-12-03
aqueous suspension
Méthodes générales d'essai des pigments et matières de charge —
Partie 9: Détermination du pH d'une suspension aqueuse
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
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INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 256
General methods of test for
Secretariat: DIN
pigments and extenders —
Voting begins on:
Part 9:
Determination of pH value of an
Voting terminates on:
aqueous suspension
Méthodes générales d'essai des pigments et matières de charge —
Partie 9: Détermination du pH d'une suspension aqueuse
© ISO 2026
All rights reserved.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
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This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Reagents . 1
5 Apparatus . 2
6 Sampling . 2
7 Procedure . 2
8 Expression of results . 2
9 Test report . 2

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.or
...

ISO/DISFDIS 787-9:2026(en)
ISO/TC 256
Secretariat: DIN
Date: 2026-07-10-08
General methods of test for pigments and extenders —
Part 9:
Determination of pH value of an aqueous suspension
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Partie 9: Détermination du pH d'une suspension aqueuse
FDIS stage
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ISO/DISFDIS 787-9:2026(en)
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iii
Contents
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Reagents . 1
5 Apparatus . 2
6 Sampling . 2
7 Procedure . 2
8 Expression of results . 2
9 Test report . 2

© ISO #### 2026 – All rights reserved
iv
ISO/DISFDIS 787-9:2026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 256, Pigments, dyestuffs and extenders, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 298,
Pigments and extenders, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 787-9:2019), which has been technically
revised.
Th
...

PROJET FINAL
Norme
internationale
ISO/TC 256
Méthodes générales d'essai des
Secrétariat: DIN
pigments et matières de charge —
Début de vote:
2026-10-22
Partie 9:
Détermination du pH d'une
Vote clos le:
2026-12-03
suspension aqueuse
General methods of test for pigments and extenders —
Part 9: Determination of pH value of an aqueous suspension
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PROJET FINAL
Norme
internationale
ISO/TC 256
Méthodes générales d'essai des
Secrétariat: DIN
pigments et matières de charge —
Début de vote:
Partie 9: 2026-10-22
Détermination du pH d'une
Vote clos le:
2026-12-03
suspension aqueuse
General methods of test for pigments and extenders —
Part 9: Determination of pH value of an aqueous suspension
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Publié en Suisse
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ii
Sommaire Page
Avant-propos .iv
1 Domaine d'application . 1
2 Références normatives . 1
3 Termes et définitions . 1
4 Réactifs . 1
5 Appareillage . 2
6 Échantillonnage . 2
7 Mode opératoire . 2
8 Expression des résultats . 2
9 Rapport d'essai . 3

iii
Avant-propos
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