ISO/FDIS 17186

• Abstract:

  ISO 17186:2011 specifies a method for determining the thickness of the surface coating applied to leather when measured under zero compression. It is applicable to all types of leather.

• Status: Not Published
• ICS: 59.140.30 - Leather and furs
• Technical Committee: IULTCS - International Union of Leather Technologists and Chemists Societies
• Drafting Committee: IULTCS - International Union of Leather Technologists and Chemists Societies
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 16-Sep-2026
• Completion Date: 16-Sep-2026

• Consolidates: FprEN ISO 17186 - Leather - Physical and mechanical tests - Determination of surface coating thickness (ISO/FDIS 17186:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO 18674-8:2023 - Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation — Part 8: Measurement of loads: Load cells
• Effective Date: 16-Oct-2025
• Revises: ISO 17186:2011 - Leather — Physical and mechanical tests — Determination of surface coating thickness
• Effective Date: 16-Oct-2025

Overview

ISO/FDIS 17186:2026 - Leather - Physical and mechanical tests - Determination of surface coating thickness is an internationally recognized standard developed by ISO for measuring the thickness of surface coatings applied to leather under zero compression conditions. Applicable to all types of leather, this standard specifies reliable methods for quantifying the thickness of applied surface coatings, a critical factor affecting performance, quality, and regulatory compliance in the leather industry.

By following ISO/FDIS 17186, laboratories, manufacturers, and quality assurance professionals can ensure consistency and accuracy in measuring coating thickness, which is essential for product validation and conformance to market and legislative requirements.

Key Topics

ISO/FDIS 17186:2026 addresses the following essential aspects of leather surface coating evaluation:

• Scope and Applicability: Suitable for all leather types, regardless of the origin or end use.
• Principle: Measurement of surface coating thickness taken perpendicular to the coated leather surface, under zero compression, using microscopy.
• Apparatus: Use of light microscopes or scanning electron microscopes (SEM) capable of high-resolution measurements, graduated scales, calibration devices, and sample preparation tools.
• Sampling and Test Preparation: Clear guidance on methodical specimen selection and conditioning in line with ISO 2418 and ISO 2419.
• Measurement Methods:
  • Method A: Measurement of thickness at equidistant positions for statistical analysis.
  • Method B: Measurement using parallel lines, suitable for irregular surfaces.
• Data Expression: Calculation and reporting of absolute coating thickness, optionally as a percentage of total leather thickness.
• Reporting: Standardized documentation requirements for traceability and reproducibility.

Applications

Implementing ISO/FDIS 17186 offers tangible benefits across several domains within the leather industry:

• Quality Control: Ensures that leather products conform to surface coating specifications, supporting durability and intended aesthetic properties.
• Product Development: Enables R&D teams to validate new coating formulations or technologies by providing precise thickness data.
• Regulatory Compliance: Supports adherence to international product safety and environmental regulations that may mandate controls on coating thickness and materials.
• Supply Chain Assurance: Facilitates transparency and consistency for leather goods suppliers, manufacturers, and brand owners by applying international test methods.
• Performance Optimization: Assists in evaluating the functional characteristics of leather coatings, affecting flexibility, abrasion resistance, and other physical properties critical to end use.
• Customer Confidence: Provides standardized, documented evidence of product properties, enhancing consumer trust and reducing the risk of disputes.

Related Standards

For comprehensive quality management and testing in the leather industry, the following related standards should also be considered:

• ISO 2418: Leather - Chemical, physical, mechanical and fastness tests - Position and preparation of specimens for testing
• ISO 2419: Leather - Physical and mechanical tests - Specimen and test piece conditioning
• IULTCS Methods: International established protocols for leather sampling and testing, often harmonized with ISO.
• Other ISO Leather Standards: Covering additional physical, mechanical, and chemical properties relevant to different leather goods and applications.

By integrating ISO/FDIS 17186 with these complementary standards, organizations can build a robust, repeatable framework for leather testing, ensuring product excellence and global market access.

Keywords: ISO 17186, leather testing, surface coating thickness, physical tests, mechanical tests, microscopy, quality control, leather industry standards, international standard, coating measurement, compliance.

FINAL DRAFT
International
Standard
ISO/FDIS 17186
IUP 41
IULTCS
Leather — Physical and mechanical
Voting begins on:
tests — Determination of surface
2026-09-16
coating thickness
Voting terminates on:
2026-11-11
Cuir — Essais physiques et mécaniques — Détermination de
l'épaisseur du revêtement de surface
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
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
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
IUP 41:2026(en) © ISO 2026
FINAL DRAFT
IUP 41:2026(en) International
Standard
ISO/FDIS 17186
IUP 41
IULTCS
Leather — Physical and mechanical
Voting begins on:
tests — Determination of surface
coating thickness
Voting terminates on:
Cuir — Essais physiques et mécaniques — Détermination de
l'épaisseur du revêtement de surface
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.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Reference number
Published in Switzerland ISO/FDIS 17186:2026(en)
IUP 41:2026(en) © ISO 2026
ii
IUP 41:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling and test piece preparation . 2
7 Procedure . 2
7.1 General descriptions .2
7.1.1 Principles of measurement .2
7.1.2 Magnification and calibration .3
7.2 Method A — Based on the measurement of single values on equidistant positions.3
7.2.1 Measurement using measuring marks of a suitable computer program as
analysis unit of the microscope.3
7.2.2 Measurement using a light microscope fitted with a graduated scale .4
7.3 Method B — Based on a measurement using parallel lines .5
7.3.1 Measurement using measuring lines of a suitable computer program as analysis
unit of the microscope .5
7.3.2 Measurement using a light microscope fitted with a graduated scale .6
7.3.3 Measurement using a microscope fitted with a means of obtaining photographs .6
8 Expression of results . 7
9 Test report . 7

iii
IUP 41:2026(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 documents 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 the Physical Test Commission of the International Union of Leather
Technologists and Chemists Societies (IUP Commission, IULTCS), in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to further
the advancement of leather science and technology. IULTCS has three Commissions, which are responsible
for establishing international methods for the sampling and testing of leather. ISO recognizes IULTCS as an
international standardizing body for the preparation of test methods for leather.
This third edition cancels and replaces the second edition (ISO 17186:2011), which has been technically
revised.
The main changes are as follows:
— update of normative references;
— update of terminology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
FINAL DRAFT International Standard
IUP 41:2026(en)
Leather — Physical and mechanical tests — Determination of
surface coating thickness
1 Scope
This document specifies a method for determining the thickness of the surface coating applied to leather
when measured under zero compression. It is applicable to all types of leather.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 2418, Leather — Chemical, physical, mechanical and fastness tests — Position and preparation of specimens
for testing
ISO 2419, Leather — Physical and mechanical tests — Specimen and test piece conditioning
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
A section of leather is taken perpendicular to the coated surface. The thickness of the surface coating is
measured using a microscope and expressed as an absolute thickness. The coating thickness as a percentage
of the total thickness of the leather can be reported, if required.
5 Apparatus
5.1 Light microscope or scanning electron microscope, which can be operated with an object-field size
of 1 mm × 1 mm, or lower, and is
— fitted with a camera-image unit connected to a computer [resolution of at least (500 × 500) pixels], or
— fitted with a photographical unit, or
— equipped with an eyepiece with a graduated scale (at least 100 scale marks).
NOTE 100 scale marks correspond to a scaling of 10 µm in the object-field dimension for an object-field size of
1 mm × 1 mm.
For measurement of coating thicknesses of less than 50 µm, an object-field size of 0,4 mm × 0,4 mm or lower
shall be used. For measurement of values of less than 15 µm, a scanning electron microscope with a suitable
object-field dimension should be used.

IUP 41:2026(en)
5.2 Razor blade.
5.3 Grid or similar calibration device, reading to at least 10 µm and suitable for use in the light
microscope or scanning electron microscope.
5.4 Coating unit, using sputter or evaporation, including a suitable element or alloy (e.g. gold) for coating,
if a scanning electron microscope is used.
5.5 Specimen stubs, suitable for a scanning electron microscope.
6 Sampling and test piece preparation
6.1 Sample in accordance with ISO 2418. Condition in accordance with ISO 2419.
6.2 Cut three test pieces of approximately 10 mm × 10 mm. If there is a requirement for more than two
hides or skins to be tested in one batch, then only one test piece need be taken from each hide or skin,
provided that the overall total is not less than three pieces. Section each of the three test pieces as described
in 6.3.
6.3 Place the cutting edge of the razor blade (5.2) on the flesh side, with the blade perpendicular to the
leather surface, and pres
...

IUP 41:2026(en)
IULTCS
Secretariat: ISO
Date: 2026-07-2709-01
Leather — Physical and mechanical tests — Determination of surface
coating thickness
Cuir — Essais physiques et mécaniques — Détermination de l'épaisseur du revêtement de surface
FDIS stage
TThhiiss dr draaftft i is s susubbmmiitttteed d ttoo aa ppaarraallellel l vvoottee i inn IISSOO,, CCEEN.N.

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
IUP 41:2026(en)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling and test piece preparation . 2
7 Procedure . 2
7.1 General descriptions . 2
7.2 Method A — Based on the measurement of single values on equidistant positions . 4
7.3 Method B — Based on a measurement using parallel lines. 6
8 Expression of results . 8
9 Test report . 8

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 documents 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'sISO’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 the Physical Test Commission of the International Union of Leather
Technologists and Chemists Societies (IUP Commission, IULTCS), in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to further the
advancement of leather science and technology. IULTCS has three Commissions, which are responsible for
establishing international methods for the sampling and testing of leather. ISO recognizes IULTCS as an
international standardizing body for the preparation of test methods for leather.
This third edition cancels and replaces the second edition (ISO 17186:2011), which has been technically
revised.
The main changes are as follows:
— — update of normative references;
— — update of terminology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
FINAL DRAFT International Standard ISO/FDIS 17186:2026(en)
IUP 41:2026(en)
Leather — Physical and mechanical tests — Determination of surface
coating thickness
1 Scope
This document specifies a method for determining the thickness of the surface coating applied to leather when
measured under zero compression. It is applicable to all types of leather.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 2418, Leather — Chemical, physical, mechanical and fastness tests — Position and preparation of specimens
for testing
ISO 2419, Leather — Physical and mechanical tests — Specimen and test piece conditioning
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Principle
A section of leather is taken perpendicular to the coated surface. The thickness of the surface coating is
measured using a microscope and expressed as an absolute thickness. The coating thickness as a percentage
of the total thickness of the leather can be reported, if required.
5 Apparatus
5.1 5.1 Light microscope or scanning electron microscope, which can be operated with an object-
field size of 1 mm × 1 mm, or lower, and is
— — fitted with a camera-image unit connected to a computer ([resolution of at least (500 × 500) pixels),],
or
— — fitted with a photographical unit, or
— — equipped with an eyepiece with a graduated scale (at least 100 scale marks).
NOTE 100 scale marks correspond to a scaling of 10 µm in the object-field dimension for an object-field size of
1 mm × 1 mm.
For measurement of coating thicknesses of less than 50 µm, an object-field size of 0,4 mm × 0,4 mm or lower
shall be used. For measurement of values of less than 15 µm, a scanning electron microscope with a suitable
object-field dimension should be used.
5.2 5.2 Razor blade.
5.3 5.3 Grid or similar calibration device, reading to at least 10 µm and suitable for use in the light
microscope or scanning electron microscope.
5.4 5.4 Coating unit, using sputter or evaporation, including a suitable element or alloy (e.g. gold) for
coating, if a scanning electron microscope is used.
5.5 5.5 Specimen stubs, suitable for a scanning electron microscope.
6 Sampling and test piece preparation
6.1 6.1 Sample in accordance with ISO 2418. Condition in accordance with ISO 2419.
6.2 6.2 Cut three test pieces of approximately 10 mm × 10 mm. If there is a requirement for more than
two hides or skins to be tested in one batch, then only one test piece need be taken from each hide or skin,
provided that the overall total is not less than three pieces. Section each of the three test pieces as described
in 6.36.3.
6.3 6.3 Place the cutting edge of the razor blade (5.2(5.2)) on the flesh side, with the blade
perpendicular to the leather surface, and press the blade through the whole thickness of the leather, ensuring
that the blade remains vertical. It is recommended that a new razor blade be used for each section.
If using a scanning electron microscope, stick a section prepared as described above onto a specimen stub
(5.5(5.5)) with the cut surface uppermost. Coat the stub and section in the coating unit (5.4(5.4)) so that a
sufficient image quality can be obtained.
7 Procedure
7.1 General descriptions
7.1.1 Principles of measurement
This document describes two basic principles to measure the surface coating thickness.
Method A is based on the measurement of a number of values on equidistant positions (see
Figure 1Figure 1).). It enables the determination of a standard deviation as well as a confidence interval.
Method B is based on a measurement using parallel lines (see Figure 2Figure 2).). A statistical evaluation of
the results is not possible due to the fact that the operator has to position the graduation of the grid between
peaks and troughs manually. This process already includes a calculation of the average.
Method A should be preferred.
Methods A and B can be used for light microscopes as well as for scanning electron microscopes. The working
distance and the acceleration voltage of the scanning electron microscope shall be the same for calibration
and measurement of the sample.
IUP 41:2026(en)
Key
1 leather
2 coating
3 equidistant single measurement
Figure 1 — Principle of method A
Key
1 leather
2 coating
3 graduated scale or parallel lines
Figure 2 — Principle of method B
7.1.2 Magnification and calibration
Due to the variation in the typical thickness of surface coating (e.g. 10 µm to 200 µm) and the total thickness
of leather (e.g. 800 µm to 3 000 µm), it is usually necessary to use different magnifications of the mi
...