Form 4: New Work Item Proposal
Circulation date:2018-03-14
Closing date for voting:2018-06-06

Reference number: Click here to enter text.
(to be given by Central Secretariat)

Proposer (e.g. ISO member body or A liaisonorganization)

ISO/TC Click here to enter text./SC Clickhere to enter text.

AFNOR☒ Proposal for a new PC

Secretariat

N Click here to enter text.

AFNOR

A proposal for a new work item within the scope of an existing committee shall be submitted tothe secretariat of that committee with a copy to the Central Secretariat and, in the case of a
subcommittee, a copy to the secretariat of the parent technical committee. Proposals not within
the scope of an existing committee shall be submitted to the secretariat of the ISO TechnicalManagement Board.
The proposer of a new work item may be a member body of ISO, the secretariat itself, anothertechnical committee or subcommittee, an organization in lia ison, the Technical Management
Board or one of the advisory groups, or the Secretary-General.
The proposal will be circulated to the P-members of the technical committee or subcommittee
for voting, and to the O-members for information.
IMPORTANT NOTE: Proposals without adequate justification risk rejection or referral tooriginator.
Guidelines for proposing and justifying a new work item are contained in Annex C of the
ISO/IEC Directives, Part 1.
☒ The proposer has considered the guidance given in the Annex C during the preparation of
the NWIP.
Proposal (to be completed by the proposer)
Title of the proposed deliverable.
English title:
Tableware, giftware, jewellery, luminaries — Glass clarity — Classification and test
methodFrench title (if available):
Verrerie, objets de décoration, bijouterie, luminaire — Clarté du verre — Classificationet méthode d’essai(In the case of an amendment, revision or a new part of an existing document, show
the reference number and current title)

FORM 4 – New work item proposal
Version 02/2017

Scope of the proposed deliverable.
The proposed International Standard will establish requirements for the use of the designations“clear glass” and “ultra-clear glass” for non-coloured glass according to their clarity and ironcontent. The standard will specify a procedure for measuring the clarity of glass items by means ofa spectrophotometer.
The standard will covermineral glass, andglass in items where the glass component is not covered by coating or decoration, and istherefore accessible for sampling.
The scope of this International Standard includes glass used as tableware, giftware, jewellery andluminaries. It excludes glass used in construction work, containers, medicine and laboratories, or inother types of technical applications.
Purpose and justification of the proposal*
Clear and ultra-clear glass products for tableware, giftware, jewellery, luminaries, etc. is a
growing market worldwide.
An International Standard providing a generic definition and a classification of glass clarity
will enable precise product characterization and facilitate commercial exchanges throughtransparency of information.
It is proposed that IWA 8:2009 will serve as a first version for this document as it has proved
its usefulness by being referenced in commercial documents. The proposed International
Standard will not only reuse but also improve and build upon the content of IWA 8:2009.
Since clear and ultra-clear glass are used as a material for components of a wide range ofgoods, this subject cannot be assigned to the existing ISO technical committees since they
all relate to a specific use case of all the materials involved in their respective specialty.
In particular the proposed work will target different stakeholders than the one involved in
ISO/TC 166 Ceramic ware, glassware and glass ceramic ware in contact with food , which
deals solely with ceramic ware, glassware and glass ceramic ware in contact with food, while
the proposed work also covers giftware, jewellery and luminaries. The dynamics related tostandardization for the contact with food are driven by regulation and focused on thedetermination of the migration of chemicals elements, which are completely distinct from theissues at stake in this proposal.
For similar reasons, ISO/TC 274 Light and lighting and ISO/TC 174 Jewellery and precious
metals, focused on the specific use of materials and in particular of precious metals, would
not be relevant to address the needs expressed by the stakeholders.
Therefore, expanding the scope of either existing TCs would not be appropriate. It is thus
proposed to establish a new ISO Project Committee, for which AFNOR is willing and ready toundertake the secretariat.
Consider the following: Is there a verified market need for the proposal? What
problem does this standard solve? What value will the document bring to end -users?
See Annex C of the ISO/IEC Directives part 1 for more information.
See the following guidance on justification statements on ISO Connect:
https://connect.iso.org/pages/viewpage.action?pageId=27590861

FORM 4 – New work item proposal
Version 03/2017

Preparatory work (at a minimum an outline should be included with the proposal)☐ An outline is attached ☐ An existing document to☒ A draft is attachedserve as initial basis

The proposer or the proposer's organization is prepared to undertake the preparatory
work required:
☒ Yes

☐ No

If a draft is attached to this proposal,:Please select from one of the following options (note that if no option is selected, thedefault will be the first option):☐ Draft document will be registered as new project in the committee's work
programme (stage 20.00)☒ Draft document can be registered as a Working Draft (WD – stage 20.20)☐ Draft document can be registered as a Committee Draft (CD – stage 30.00)☐ Draft document can be registered as a Draft International Standard (DIS – stage
40.00)☐ If the attached document is copyrighted or includes copyrighted content, theproposer confirms that copyright permission has been granted for ISO to use thiscontent in compliance with clause 2.13 of the ISO/IEC Directives, Part 1 (see also the
Declaration on copyright).
Is this a Management Systems Standard (MSS)?
☐ Yes ☒ No
NOTE: if Yes, the NWIP along with the Justification study (see Annex SL of theConsolidated ISO Supplement) must be sent to the MSS Task Force secretariat(tmb@iso.org) for approval before the NWIP ballot can be launched.
Indication(s) of the preferred type or types of deliverable(s) to be produced
under the proposal.
☒ International Standard☐ Technical Specification☐ Publicly Available Specification☐ Technical Report

Proposed development track☐ 18 months*☐ 24 months☒ 36 months☐ 48 months

Note: Good project management is essential to meeting deadlines. A committee
may be granted only one extension of up to 9 months for the total project
duration (to be approved by the ISO/TMB).
*DIS ballot must be successfully completed within 13 months of the project’s registration in order
to be eligible for the direct publication process

Draft project plan (as discussed with committee leadership)
Proposed date for first meeting: October 2018
Dates for key milestones: DIS submission February 2020
Publication June 2021

FORM 4 – New work item proposal
Version 03/2017

Known patented items (see ISO/IEC Directives, Part 1 for important guidance)☐ Yes ☒ No
If "Yes", provide full information as annex
Co-ordination of work: To the best of your knowledge, has this or a similar proposal
been submitted to another standards development organization?
☐ Yes ☒ No
If “Yes”, please specify which one(s):Click here to enter text.
A statement from the proposer as to how the proposed work may relate to or
impact on existing work, especially existing ISO and IEC deliverables. The
proposer should explain how the work differs from apparently similar work, or
explain how duplication and conflict will be minimized.
No other known similar work, except the IWA 8:2009.
A listing of relevant existing documents at the international, regional andnational levels.
IWA 8:2009 Tableware, giftware, jewellery, luminaries – Glass clarity – Classificationand test method

FORM 4 – New work item proposal
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Please fill out the relevant parts of the table below to identify relevant affectedstakeholder categories and how they will each benefit from or be impacted by
the proposed deliverable(s).
Benefits/impacts
Industry and commerce –large industry

Industry and commerce –SMEs

Government

Consumers

LabourThe IS will facilitatecommercial exchanges by
setting common quality
requirement and allowing
greater transparency of
information
The IS will facilitatecommercial exchanges by
setting common quality
requirement and allowing
greater transparency of
information
The IS will foster fair trade andfair competition throughtransparency of information
The IS will provide consumers
with a higher level of
information about productcharacteristics and quality//

Examples oforganizations/companies tobe contacted
Manufacturers and retailers

Manufacturers and retailers

Competent authorities(governmental inspection
services)
Click here to enter text.

Click here to enter text.

Academic and researchbodiesStandards application
businesses
Non-governmentalorganizations

The IS will provide common
testing procedures
A certification mark could be
developed
Click here to enter text.

Testing laboratories

Other (please specify)

Click here to enter text.

Click here to enter text.

Certification bodies
Click here to enter text.

Liaisons:

Joint/parallel work:

A listing of relevant external internationalorganizations or internal parties (other ISO
and/or IEC committees) to be engaged as
liaisons in the development of thedeliverable(s).

Possible joint/parallel work with:

ISO/TC 136 Furniture☐ IEC (please specify committee ID)

Click here to enter text.
☐ CEN (please specify committee ID)

Click here to enter text.

ISO/TC 166 Ceramic ware, glassware andglass ceramic ware in contact with food

☐ Other (please specify)

ISO/TC 174 Jewellery and precious metals

Click here to enter text.

ISO/TC 274 Light and lighting

FORM 4 – New work item proposal
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A listing of relevant countries which are not already P-members of thecommittee.
Austria, Belgium, China, Czech Republic, France, Germany, Indonesia, Italy,
Netherland, Portugal, Spain, Turkey, United Kingdom, USA
Note: The committee secretary shall distribute this NWIP to the countries listed above
to see if they wish to participate in this work
Proposed Project Leader (name ande-mail address)

Name of the Proposer(include contact information)

Ivan Litvinenko

Ms PIAT RAGOT(gwenaelle.piatragot@afnor.org)

This proposal will be developed by:☐ An existing Working Group (please specify which one: Click here to enter text.)☐ A new Working Group (title: Click here to enter text.)(Note: establishment of a new WG must be approved by committee resolution)☐ The TC/SC directly☒ To be determined
Supplementary information relating to the proposal☐ This proposal relates to a new ISO document;☐ This proposal relates to the adoption as an active project of an item currently
registered as a Preliminary Work Item;☐ This proposal relates to the re-establishment of a cancelled project as an active
project.
Other:
Replacement of IWA 8:2009
Maintenance agencies and registration authorities☐ This proposal requires the service of a maintenance agency. If yes, please
identify the potential candidate:

Click here to enter text.
☐ This proposal requires the service of a registration authority. If yes, please
identify the potential candidate:

Click here to enter text.
NOTE: Selection and appointment of the MA or RA is subject to the procedure outlinedin the ISO/IEC Directives, Annex G and Annex H, and the RA policy in the ISO
Supplement, Annex SN.
☒ Annex(es) are included with this proposal (give details)
See working draft attached

FORM 4 – New work item proposal
Version 03/2017

Additional information/questions
For more information or question, please contact Ms PIAT RAGOT at
gwenaelle.piatragot@afnor.org

FORM 4 – New work item proposal
Version 03/2017

© ISO #### – All rights reserved

ISO/WD XXX:2017(E)ISO TC XXXSecretariat: XXX

Tableware, giftware, jewellery, luminaries — Glass clarity —Classification and test method
Verrerie, objets de décoration, bijouterie, luminaire — Clarté du verre — Classification etméthode d’essai

WD stage
Warning
This document is not an ISO International Standard. It is distributed for review and comment. It is subject tochange without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights ofwhich they are aware and to provide supporting documentation.

ISO/WD 8:2017(E)© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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 theinternet or an intranet, without prior written permission. Permission can be requested from either ISO at theaddress below or ISO’s member body in the country of the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
copyright@iso.org
www.iso.org

2© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)Contents
Page
Foreword ................................................................................................................................................................................... 4
Introduction ............................................................................................................................................................................. 5
1

Scope ........................................................................................................................................................................... 6

2

Specifications ........................................................................................................................................................... 6

2.1

General............................................................................................................................................................................... 6

2.2

Specifications for ultra-clear glass ......................................................................................................................... 7

2.3

Specifications for clear glass..................................................................................................................................... 7

3

Test methods ............................................................................................................................................................ 7

3.1

General............................................................................................................................................................................... 7

3.2

Apparatus ......................................................................................................................................................................... 7

3.3

Sampling ........................................................................................................................................................................... 8

3.4

Sample preparation ...................................................................................................................................................... 8

Annex A (normative) Determination of the lightness L* and chroma C* ........................................................ 10

A.1

Applicability ................................................................................................................................................................. 10

A.2

Principle ......................................................................................................................................................................... 10

A.3

Measurement of lightness L* and chroma C*.................................................................................................. 10

A.4

Estimation of the experimental reproducibility ............................................................................................ 12

Annex B (normative) Determination of the iron oxide content ......................................................................... 13
Bibliography ........................................................................................................................................................................... 14© ISO 2017 – All rights reserved

3ISO/WD 8:2017(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. Each member body interested in a subject for which a technicalcommittee has been established has the right to be represented on that committee. Internationalorganizations, 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 ofelectrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance aredescribed in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for thedifferent types of ISO documents should be noted. This document was drafted in accordance with theeditorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject ofpatent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does notconstitute an endorsement.
For an explanation on 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 the following URL:
www.iso.org/iso/foreword.html.
The committee responsible for this document is Technical Committee [or Project Committee] ISO/TC[or ISO/PC] ###, [name of committee].

4© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)Introduction
This International Standard is intended to provide a generic definition and classification of glass clarity
to permit a global understanding of consumer quality requirements, with a corresponding method tomeasure glass clarity.
For glass clarity, spectrophotometric measurement is performed in accordance with CIE 15:2004
with a predefined choice of illuminate and observer. Measurement on the sample at two different
thicknesses permits calculation of internal transmission for a defined intermediate thickness andindicates glass clarity irrespective of the refractive index value. The same methodology applies for all
mineral glasses.
This method has been verified in accordance with visual inspection with a light cabinet. In addition,
preliminary collaborative studies have confirmed the results of these measurements as being coherent
with both consumer perception and quality recognition.
As it is well known that iron is by far the main contaminant of glass raw materials affecting thetransparency and colorimetric purity of the glass, the iron content has been considered as an additional
criterion.
This International Standard does not concern lead crystal as defined in EU Council Directive 69/493/EEC,
which has its own characteristics with respect to density and refraction index.

© ISO 2017 – All rights reserved

5ISO/WD 8:2017(E)

Tableware, giftware, jewellery, luminaries — Glass clarity —Classification and test method
1 ScopeThis International Standard establishes requirements for the use of the glass designations “clear glass”
and “ultra-clear glass” for non-coloured glass items according to their clarity and iron content. This
International Standard specifies a procedure for measuring the clarity of glass items by means of aspectrophotometer.
This International Standard is applicable to⎯ mineral glasses, and— glass items where a part is not covered by coating or decoration, and is therefore available forsampling.
This International Standard is applicable to the use of glass as tableware, giftware, jewellery andluminaries.
This International Standard is not applicable to the use of glass in the context of building, containers,
medicine and laboratories, and to other technical uses of glass

2

Normative references

There are no normative references in this document.

3

Terms and definitions

No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:— ISO Online browsing platform: available at http://www.iso.org/obp— IEC Electropedia: available at http://www.electropedia.org/

4

Specifications

4.1 General
The classification of the samples of glass in terms of clarity is based on three criteria:— lightness, L*;— chroma, C*;— iron content of the material.
6© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)The iron content is a main contaminant influencing the transparency and colour of the glass; the value isexpressed in iron oxide (Fe2O3) in mg/kg.
NOTE
The best classification of clarity is obtained for the maximum value of lightness L* at 100 and theminimum value of chroma C* at zero.

4.2 Specifications for ultra-clear glass
Ultra-clear glass shall have:— lightness L* ≥ 98,8;— chroma C* ≤ 0,5;
— iron oxide content ≤ 140 mg/kg.
If one or more of these criteria are not reached, the glass cannot be classified as ultra-clear glass.

4.3 Specifications for clear glass
Clear glass shall have:— lightness L* ≥ 98,0;— chroma C* ≤ 0,5;
— iron oxide content ≤ 200 mg/kg.
If one or more of these criteria are not reached, the glass cannot be classified as clear glass.

5

Test methods

5.1 General
The sample shall be prepared in accordance with 3.3 and 3.4. The same sample shall be used tocharacterize the three criteria, in accordance with the following two determination methods:— Annex A shall apply for the determination of lightness L* and chroma C*;— Annex B shall apply for the determination of the iron oxide content.

5.2 Apparatus
3.2.1

Double-beam spectrophotometer, preferably with integrating sphere.

3.2.2

X-ray fluorescence spectrometer, with wavelength dispersion.

3.2.3

Non-metallic hammer.

3.2.4

Non-metallic plate.

3.2.5

Platinum crucible, compatible with the final dimensions of the sample(s).

© ISO 2017 – All rights reserved

7ISO/WD 8:2017(E)3.2.6Electric oven, capable of maintaining a temperature of 1 300 °C for a duration of 16 h.

3.2.7

Polishing device.

3.2.8

Manual grinding device, with silicium carbide (SiC) abrasive.

3.2.9

Automatic grinding machine.

3.2.10 Automatic polishing device.

5.3 Sampling
5.3.1

GeneralThe sampling is carried out to prepare two pieces of glass:— the first with a minimum dimension of 30 mm for one face;— the second with a minimum dimension of 10 mm for one face.
The two other dimensions shall be greater than the slide dimensions of the spectrophotometer (3.2.1)
for the two pieces.
5.3.2

CuttingCut a glass block from the glass item (e.g. tumblers with a thick bottom).
For glass items covered with coating or decoration, or for glass items of which the minimum dimensionsof the sample cannot be reached,— melt a sufficient quantity of glass not covered with coating or decoration, approximately 200 g;— crush with a non-metallic hammer (3.2.3) on a non-metallic plate (3.2.4);— melt in a platinum crucible (3.2.5) in an electric oven (3.2.6) for a duration of at least 8 h at 1 300 °C,
in order to obtain a good quality of glass;— check for the absence of seeds or bubbles;— after solidification of the glass, put the crucible outside the furnace in a cold water stream to separate
the glass from the crucible.
The resulting sample is annealed to avoid residual stresses.

5.4 Sample preparation
5.4.1

GeneralFor the internal transmission measurements, prepare one sample with at least one face providing 10 mmthickness for measurement and the other sample with at least one face providing 30 mm thickness formeasurement (see 3.3.1). The sample thicknesses where the light travels are (10 ± 0,05) mm and(30 ± 0,05) mm respectively.

8© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)The dimensions of the samples (cubes) should fit the sample holder of the spectrophotometer that isused.
The preparation of the cubes of glass samples are carried out in accordance with the usual procedures ofthe laboratories, applying a polishing device (3.2.7) on the two faces in the optical way of transmission(light path).
5.4.2

Cutting

Each sample is cut from the part of a glass block that is homogenous and free of bubbles, cords and anyother defects, by means of a diamond saw, to dimensions that are— approximately 0,5 mm greater than the required final dimensions before manual grinding withsilicon carbide abrasive (see 3.2.8), or— approximately 5 mm greater than the required final dimensions before grinding with an automatic
machine as used in the glass industry (see 3.2.9).
5.4.3

Grinding

In the manual grinding procedure, a sample cube is ground under flowing water to obtain parallel
surfaces at each measured face by means of turning grinding disks (see 3.2.8), using coarse grain size ofsilicon carbide granules. The final step of grinding is carried out on a flat glass surface, using fine grain
size of silicon carbide (less than 25 µm) polishing slurry to obtain the exact final dimensions of thesamples and the right surface appearance. With a grinding machine (see 3.2.9), the cube is grinded
automatically by 1,5 mm steps (or less). The cube is machined on one side and then on the other side toobtain parallel sides. The thickness is then reduced to 10 mm or 30 mm.
In both procedures (manual and automatic), the parallelism of the surfaces and the dimensions arecontinuously checked between the grinding steps.
5.4.4

Polishing

Only the two surfaces of the glass sample cube from where the light travels in the spectrophotometer
need to be polished.
In the manual procedure, the sample cubes are polished on a turning polishing wheel (see 3.2.7) using
cerium oxide powder solution, obtained by diluting approximately 100 g of powder with 500 ml of water.
Polishing can also be achieved automatically by a polishing machine using cerium oxide (as used in theglass industry) (see 3.2.10).
Lastly, a verification is made that the thickness is within the tolerance of ± 0,05 mm, as is the parallelismof the ground and polished sample deviation range of the required dimensions. The polished sample iscleaned using alcohol before the measurement.
Only glass samples without optical distortion and surface defects shall be used on the polished surfaces.
NOTE
Optical distortion is checked by viewing a grid through the glass sample. If there are bubbles or any otherdefects, deviation and distortion of the observed image occur.

© ISO 2017 – All rights reserved

9ISO/WD 8:2017(E)Annex A(normative)
Determination of the lightness L* and chroma C*

A.1 Applicability
The procedure in this annex describes a method for determining lightness L* and chroma C*, in order toclassify glass items in accordance with the specifications for ultra-clear glass (see 2.2) and for clear glass(see 2.3).
This procedure applies to samples prepared in accordance with 3.3 and 3.4.

A.2 Principle
Spectrophotometric measurement is performed in accordance with CIE 15:2004 with a predefined choiceof illuminate and observer.
The total transmission of the samples is measured in order to calculate the internal transmission. The
colorimetric values are then calculated from internal transmission data.

A.3 Measurement of lightness L* and chroma C*
A.3.1 General
The spectral curves of total transmittance (internal and surface) are measured every 5 nm on the spectral
range from 380 nm to 780 nm on the sample, with the two thicknesses of 10 mm and 30 mm, using adouble-beam ultraviolet-visible (UV-Vis) spectrophotometer (see 3.2.1).
Geometry (transmittance/reflectance) 0° / 8°, reference: air. Temperature of the room: (22 ± 2) °C.
The laboratory shall take the necessary actions to maintain an adequate level of calibration of theequipment.
A.3.2 Calculation of the internal transmission
A.3.2.1 Principle
Measurement on the sample at two different thicknesses permits calculation of internal transmission fora defined intermediate thickness and indicates glass clarity irrespective of the refractive index value.
A.3.2.2 Total transmittance measurement TλMeasure the total transmittances Tλ,d1 and Tλ,d2 of the sample at two different thicknesses, d1 and d2, inorder to determine the transmittance of a thickness x, as d1 < x < d2 (see A.3.1).
For the purposes of this International Standard, use d1 = 10 mm and d2 = 30 mm, with x = 20 mm (seeA.3.1).

10© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)A.3.2.3 Calculation of the extinction coefficient Kλ
The extinction coefficient, Kλ, is calculated as shown in Equation (A.1):
,

=−

,

(A.1)

where
Kλ

is the extinction coefficient at the wavelength λ;Tλ,d1

is the transmittance value of the glass item sample of thickness d1 (10 mm) at wavelength λ;Tλ,d2is the transmittance value of the glass item sample of thickness d2 (30 mm) at wavelength λ.

A.3.2.4 Calculation of the internal transmission, Tiλ, for a chosen thickness (20 mm)
From the extinction coefficient (see A.3.2.3), the internal transmission, Tiλ, is calculated as shown inEquation (A.2):
Tiλ =

iλ
eλ

=e-K • χ
λ

(A.2)

where
χ

is the chosen thickness (20 mm);Tiλis the internal transmission;

Φiλis the light flow with the wavelength λ entering in an isotropic element, non-luminescent,non-phototropic and optically clear;Φeλis the outgoing light flow.

A.3.3 Calculation of lightness L* and chroma C*
From the obtained spectral curve of internal transmittance, the colorimetric values are calculated incolour space developed by the International Commission on Illumination (CIE) in CIE 1976 (CIELAB) (seeISO 11664-4), in Cartesian coordinates L*a*b* and in cylindrical coordinates L*C*h, for— the main reference illuminate D65 (see ISO 11664-2), and— the observer 10° (see ISO 11664-1).
All colorimetric calculations are carried out in accordance with the recommendations of CIE 15:2004.
NOTE 1
These colour measurements can be validated and correlated with visual observations under lightcabinet, with an illuminate D65 and under an illumination of 1 000 lux, and on a grey and uniform back of lightness
L* = 50.
NOTE 2
D65 is the reference illuminate. It is advisable that the user of this International Standard take into
consideration the possible effects of a measurement under another illuminate.

© ISO 2017 – All rights reserved

11ISO/WD 8:2017(E)

A.4 Estimation of the experimental reproducibility
One laboratory performed ten measurements of the same sample on ten different days with the same
instrument and operator. The obtained standard deviations of the measurements are as follows:⎯

standard deviation on lightness L* = 0,028;⎯

standard deviation on chroma C* = 0,026.

A round robin test was performed by seven laboratories. The average values of lightness L* andchroma C* were determined on 17 different samples covering a large range of glasses on the market. The
standard deviations for these values were obtained. The main results are given in Table A.1.
Table A.1 — Reproducibility study for determination method in this annex
Parameters

Range of measurement

Standard deviation

Lightness L*

From 97,1 to 99,7

From 0,06 to 0,15

Chroma C*

From 0,07 to 0,53

From 0,01 to 0,08

NOTE
Table A.1 gives an estimation of the reproducibility. It is advisable that a further collaborative study be
carried out in order to obtain reproducibility and repeatability values in accordance with ISO 5725-1.

12© ISO 2017 – All rights reserved

ISO/WD 8:2017(E)Annex B
(normative)
Determination of the iron oxide content

The iron content of the material is also taken into consideration, according to the value of the iron oxide
content as measured by X-ray fluorescence in the same glass samples.
For the X-ray fluorescence calibration and measures, refer to the publications listed in the Bibliography
and use certified standard material.
Standard materials are currently available from the German Federal Institute for Material Research andTesting1). Other certified standard materials are also available.
If appropriate certified standard materials are not available in the laboratory, chemical methods shall be
employed.

1)

Bundesanstalt für Materialforschung und -prüfung (BAM).

© ISO 2017 – All rights reserved

13ISO/WD 8:2017(E)Bibliography[1]

ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1:
General principles and definitions[2]

ISO 11664-12), Colorimetry — Part 1: CIE standard colorimetric observers[3]

ISO 11664-23), Colorimetry — Part 2: CIE standard illuminants[4]

ISO 11664-44) , Colorimetry — Part 4: CIE 1976 L*a*b* Colour space[5]

CIE 15:2004, Colorimetry, 3rd edition[6]

ASTM E1172-87 (2003), Standard Practice for Describing and Specifying a WavelengthDispersive X-Ray Spectrometer[7]

ASTM E1361-02 (2007), Standard Guide for Correction of Interelement Effects in X-Ray
Spectrometric Analysis[8]

ASTM E1621-05, Standard Guide for X-Ray Emission Spectrometric Analysis[9]

ASTM E1622-94 (1999)e15), Standard Practice for Correction of Spectral Line Overlap in
Wavelength- Dispersive X-Ray Spectrometry[10]

KIPPHARDT, H. and MATSCHAT, R., “Traceability and uncertainty of chemical measurement
results exemplified in the frame of the certification and the use of the glass CRM BAM-S005”, in:Rivista della Stazione Sperimentale del Vetro, 2007, vol. 37, No. 6, pp.19-23

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ISO 11664-1 is identical to CIE S 014-1.
ISO 11664-2 is identical to CIE S 014-2.
ISO 11664-4 is identical to CIE S 014-4.
Withdrawn 2006.

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