ISO 18768-1:2022

INTERNATIONAL ISO
STANDARD 18768-1
First edition
2022-06
Organic coatings on aluminium and
its alloys — Methods for specifying
decorative and protective organic
coatings on aluminium —
Part 1:
Powder coatings
Couches organiques sur l’aluminium et ses alliages — Méthodes
de spécification des revêtements décoratifs et protecteurs sur
aluminium —
Partie 1: Revêtements par poudre
Reference number
© ISO 2022
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Published in Switzerland
ii
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Information to be supplied by the customer to the surface processor .3
5 Metal preparation and pretreatment . 4
5.1 Material (substrate) . 4
5.2 Pretreatment of the substrate . 4
5.2.1 General . 4
5.2.2 Degreasing, etching and rinsing. 5
5.2.3 Anodic oxidation coatings . 5
5.2.4 Chemical conversion coatings . 5
5.2.5 Alternative pretreatment . 5
6 Categories . 6
7 Tests . 7
7.1 General . 7
7.2 Appearance . 8
7.2.1 General . 8
7.2.2 Measurement . 8
7.2.3 Requirement . 8
7.3 Colour . 8
7.3.1 General . 8
7.3.2 Visual method . 8
7.3.3 Instrumental method . 9
7.4 Gloss . 9
7.4.1 General . 9
7.4.2 Visual method . 9
7.4.3 Instrumental method . 9
7.5 Thickness . 10
7.5.1 General . 10
7.5.2 Measurement . 10
7.5.3 Requirement . 10
7.6 Hardness . 10
7.6.1 General . 10
7.6.2 Pencil hardness test . . 11
7.6.3 Buchholz indentation test . 11
7.7 Adhesion . 11
7.7.1 Dry adhesion test . 11
7.7.2 Wet adhesion test.12
7.8 Impact resistance .12
7.8.1 General .12
7.8.2 Falling-weight test .12
7.8.3 DuPont test . 13
7.9 Abrasion resistance . . 13
7.9.1 Measurement . 13
7.9.2 Requirement .13
7.10 Cupping test. 14
7.10.1 Measurement . 14
7.10.2 Requirement . 14
7.11 Cylindrical mandrel bend test . 14
7.11.1 Measurement . 14
iii
7.11.2 Requirement . 14
7.12 Processing resistance . 14
7.12.1 Measurement . 14
7.12.2 Requirement . 14
7.13 Chemical resistance . 14
7.13.1 General . 14
7.13.2 Acid resistance . 15
7.13.3 Alkali resistance .15
7.13.4 Detergent resistance . 15
7.13.5 Mortar resistance . 16
7.14 Solvent resistance . 16
7.14.1 Measurement . 16
7.14.2 Requirement . 17
7.15 Corrosion resistance . 17
7.15.1 General . 17
7.15.2 Neutral salt spray (NSS) test . 17
7.15.3 Acetic acid salt spray (AASS) test . 18
7.15.4 Copper-accelerated acetic acid salt spray (CASS) test . 18
7.15.5 Cyclic corrosion test . 19
7.15.6 Filiform corrosion resistance . 19
7.15.7 Resistance to humid atmosphere containing sulfur dioxide . 19
7.16 Humidity resistance .20
7.16.1 Measurement . 20
7.16.2 Requirement .20
7.17 Boiling water resistance .20
7.17.1 Measurement . 20
7.17.2 Requirement . 21
7.18 Weathering resistance . 21
7.18.1 General . 21
7.18.2 Outdoor exposure test. 21
7.18.3 Accelerated weathering resistance . 22
7.19 Sealing compounds adhesion . 23
7.19.1 Measurement .23
7.19.2 Requirement .23
Annex A (informative) Summary of information to be supplied by the customer to the
surface processor .24
Annex B (informative) Coating powders .27
Annex C (informative) Categories for architectural application .28
Bibliography .29
iv
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent 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 not
constitute an endorsement.
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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 79, Light metals and their alloys,
Subcommittee SC 2, Organic and anodic oxidation coatings on aluminium.
A list of all parts in the ISO 18768 series can be found on the ISO website.
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.
v
Introduction
There are three major surface treatments on aluminium and its alloys:
a) anodic oxidation coatings;
b) organic coatings;
c) combined coatings of anodic oxidation coatings and organic coatings.
This document and ISO 18768-2 provide the performance requirements and test methods for b) organic
coatings.
Performance requirements and test methods for a) anodic oxidation coatings are given in ISO 7599 and
for c) combined coatings of anodic oxidation coatings and organic coatings in ISO 28340.
It is assumed that users are familiar with other relevant international and regional standards. Those
standards should be respected, and this document adopts optional systems in such cases.
vi
INTERNATIONAL STANDARD ISO 18768-1:2022(E)
Organic coatings on aluminium and its alloys — Methods
for specifying decorative and protective organic coatings
on aluminium —
Part 1:
Powder coatings
1 Scope
This document specifies methods for specifying decorative and protective powder coatings on
aluminium and its alloys. It defines the characteristic properties of powder coatings and provides
testing methods with minimum performance requirements, with reference to the application and the
aggressiveness of the environment in which the coated aluminium exists.
This document does not apply to coil coatings on aluminium.
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 1463, Metallic and oxide coatings — Measurement of coating thickness — Microscopical method
ISO 1519, Paints and varnishes — Bend test (cylindrical mandrel)
ISO 1520, Paints and varnishes — Cupping test
ISO 2360, Non-conductive coatings on non-magnetic electrically conductive base metals — Measurement
of coating thickness — Amplitude-sensitive eddy-current method
ISO 2409, Paints and varnishes — Cross-cut test
ISO 2810, Paints and varnishes — Natural weathering of coatings — Exposure and assessment
ISO 2813, Paints and varnishes — Determination of gloss value at 20°, 60° and 85°
ISO 2815, Paints and varnishes — Buchholz indentation test
ISO 3892, Conversion coatings on metallic materials — Determination of coating mass per unit area —
Gravimetric methods
ISO 4623-2, Paints and varnishes — Determination of resistance to filiform corrosion — Part 2: Aluminium
substrates
ISO 4628-1, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and
designation system
ISO 4628-2, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of
blistering
ISO 4628-10, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 10: Assessment of degree of
filiform corrosion
ISO 6270-1, Paints and varnishes — Determination of resistance to humidity — Part 1: Condensation
(single-sided exposure)
ISO 6270-2, Paints and varnishes — Determination of resistance to humidity — Part 2: Condensation (in-
cabinet exposure with heated water reservoir)
ISO 6270-3, Paints and varnishes — Determination of resistance to humidity — Part 3: Condensation (in-
cabinet exposure with heated, bubbling water reservoir)
ISO 6272-1, Paints and varnishes — Rapid-deformation (impact resistance) tests — Part 1: Falling-weight
test, large-area indenter
ISO 6272-2, Paints and varnishes — Rapid-deformation (impact resistance) tests — Part 2: Falling-weight
test, small-area indenter
ISO 8251, Anodizing of aluminium and its alloys — Measurement of abrasion resistance of anodic oxidation
coatings
ISO 8993, Anodizing of aluminium and its alloys — Rating system for the evaluation of pitting corrosion —
Chart method
ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests
ISO 15184, Paints and varnishes — Determination of film hardness by pencil test
ISO 16474-2, Paints and varnishes — Methods of exposure to laboratory light sources — Part 2: Xenon-arc
lamps
ISO 16474-3, Paints and varnishes — Methods of exposure to laboratory light sources — Part 3: Fluorescent
UV lamps
ISO 22479, Corrosion of metals and alloys — Sulfur dioxide test in a humid atmosphere (fixed gas method)
ISO 28340:2013, Combined coatings on aluminium — General specifications for combined coatings of
electrophoretic organic coatings and anodic oxidation coatings on aluminium
ASTM C207, Standard Specification for Hydrated Lime for Masonry Purposes
ASTM D2794, Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation
(Impact)
ASTM D7869, Standard Practice for Xenon Arc Exposure Test with Enhanced Light and Water Exposure for
Transportation Coatings
ASTM G85-19, Standard Practice for Modified Salt Splay (Fog) Testing
GSB International, GSB QR AL 631-7 ST 663-7, International Quality Regulations For the Coating of
Building Components
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
3.1
powder coating
continuous layer of coating powder applied to the aluminium or aluminium alloy substrate, which is
protective and/or decorative
3.2
reference sample
reference specimen
sample which defines the criteria for acceptable properties
Note 1 to entry: This may be agreed between the customer and the surface processor.
3.3
significant surface
part of the article covered or to be covered by the coatings, and for which the coatings are essential for
service and/or appearance
3.4
test specimen
single sample of the final product to be used for testing
4 Information to be supplied by the customer to the surface processor
In order to coat the product correctly and depending on the application, the following information
should be supplied by the customer to the surface processor, if necessary, in consultation with the
aluminium supplier and/or the surface processor.
A summary of the references to this information is given in Annex A.
a) a reference to this document, i.e. ISO 18768-1;
b) the intended service use of the article to be coated;
c) the environmental categories of the intended service (see Clause 6);
d) the specification of the aluminium (chemical composition and temper designations) to be coated;
e) an indication of the significant surface(s) of the product to be coated;
f) the preferred position and maximum size of contact marks;
g) details of any formal sampling plans required;
h) the type of pretreatment;
i) mass loss by etching;
j) thickness of the anodic oxidation coating or mass of the chemical conversion coating used for
pretreatment;
k) the type of coating process to be used;
l) the quality of appearance required;
m) the acceptable limits of colour variation by agreed reference samples;
n) the colour difference of the coating between the test specimen and the reference samples using a
colour difference meter;
o) the acceptable limits of gloss variation by agreed reference samples;
p) the value range of the gloss measured by equipment;
q) the thickness of coating;
r) the hardness of coating;
s) the dry adhesion of coating;
t) the wet adhesion of coatings (boiling water resistance);
u) the impact resistance (excluding anodic oxidation coating for pretreatment);
v) the abrasion resistance of coating;
w) the cupping resistance (excluding anodic oxidation coating for pretreatment);
x) the flexibility of coating (excluding anodic oxidation coating for pretreatment);
y) the processing resistance, such as cutting, milling or drilling;
z) the solvent resistance of coating;
aa) the humidity resistance;
bb) the type of chemical resistance to be used;
cc) the detergent resistance;
dd) the alkali resistance;
ee) the mortar resistance;
ff) the acid resistance;
gg) the corrosion resistance;
hh) the resistance to a humid atmosphere containing sulfur dioxide;
ii) the filiform corrosion resistance;
jj) the weathering resistance;
kk) the accelerated weathering resistance;
ll) the sealing compounds adhesion.
5 Metal preparation and pretreatment
5.1 Material (substrate)
Aluminium and its alloys are classified in accordance with ISO 209.
5.2 Pretreatment of the substrate
5.2.1 General
Before the application of the coating, a pretreatment coating should be applied. This pretreatment may
be one of the following:
a) anodic oxidation coating;
b) chemical conversion coating with aqueous solutions containing either chromate ions or chromate
and phosphate ions, without applying an electric current;
c) alternative pretreatment (e.g. chromium-free systems).
After the chemical conversion coating process, the substrate is normally rinsed with deionized water
(preferably below 30 µS/cm at 20 °C) and dried.
There are also some coatings used mainly for decorative purposes, which do not need to be pretreated
before coating.
If a non-rinsing pretreatment is applied, the last rinsing is carried out before the conversion coating
process.
5.2.2 Degreasing, etching and rinsing
All surface contaminants such as greases, lubricants and residues shall be removed using alkaline or
acidic solutions and/or solvents in appropriate combinations. Before the conversion stage, the substrate
shall be thoroughly cleaned.
Mass loss before and after etching should be measured by the mass of a test specimen. It should be no
2 2
less than 1 g/m , and preferably 2 g/m or more.
5.2.3 Anodic oxidation coatings
The anodic oxidation coating for pretreatment should be chosen so as to produce an anodic oxidation
coating with a thickness of 3 μm to 10 μm without chalking and surface flaws. It shall be measured using
an eddy current meter in accordance with ISO 2360. After the pretreatment, rinse the test specimen
with deionized water to remove the acid from the surface. The anodic oxidation coating should not be
sealed.
The time between anodic oxidation pretreatment and powder coating should be less than 72 h. If the
time between the anodic oxidation pretreatment and powder coating is more than 24 h, the anodic
oxidation pretreatment should be tested by a dye spot test in accordance with ISO 2143. The intensity
of the stain should be level 5.
5.2.4 Chemical conversion coatings
A chemical conversion coating shall be produced by application of the appropriate solution.
Chromate conversion coatings vary in colour from iridescent yellow to golden tan. The coatings are
characterized by the presence of chromium and the absence of phosphate.
Phosphate conversion coatings vary in colour from iridescent to various shades of green. The coatings
are characterized by the presence of both chromate and phosphate.
The surface density of conversion coatings shall be agreed between the customer and the surface
processor. In the absence of such an agreement, the mass of the chromate coatings should be between
2 2 2 2
0,4 g/m and 1,0 g/m for chromate conversion coatings and between 0,4 g/m and 1,2 g/m for
chromate-phosphate conversion coatings. They shall be measured in accordance with ISO 3892.
If the coating is applied with delay or interruption after pretreatment (within 16 h), the maximum
temperature on the metal surface of drying should be as follows:
— 65 °C for chromate coatings;
— 85 °C for chromate-phosphate coatings.
5.2.5 Alternative pretreatment
Alternative pretreatments, e.g. chromium-free system, or other processes may be specified but shall be
agreed between the customer and the surface processor taking into consideration the recommendations
from the chemical supplier.
6 Categories
Typical applications of the powder coating are shown in Table B.1.
There are two typical environmental categories: corrosivity and UV radiation.
The corrosion protection and the adhesion of the coating on the aluminium is mainly determined by
the surface pretreatment before coating. For this reason, the surface pretreatment should be selected
according to the corrosivity category. It is recommended that the corrosivity category is defined in the
specification.
The permanent colour stability of a coating and the decorative appearance of the coated surface depends
on the UV resistance of the coating material. For this reason, the coating material should be selected
based on the UV category. It is recommended that the UV category is defined in the specification.
Examples of typical applications of powder coatings for architectural application are shown in
Tables C.1 and C.2.
The corrosivity category defined by the corrosion effects given in ISO 9223 are shown in Table 1. The
UV categories are shown in Table 2.
Table 1 — Description of typical atmospheric environments
related to the estimation of corrosivity categories
b
Typical environments — Examples
Corrosivity Corrosiv-
a
category ity
Indoor Outdoor
C1 Very low Heated spaces with low relative Dry or cold zone, atmospheric environ-
humidity and insignificant pollution, ment with very low pollution and time
e.g. offices, schools, museums. of wetness, e.g. certain deserts, Central
Arctic/Antarctica.
C2 Low Unheated spaces with varying Temperate zone, atmospheric environ-
temperature and relative humidity. ment with low pollution (SO < 5 µg/m ),
Low frequency of condensation and e.g. rural areas, small towns.
low pollution, e.g. storage, sport halls.
Dry or cold zone, atmospheric environ-
ment with short time of wetness, e.g.
deserts, subarctic areas.
C3 Medium Spaces with moderate frequency of Temperate zone, atmospheric
condensation and moderate pollution environment with medium pollution
3 3
from production process, e.g. food- (SO : 5 µg/m to 30 µg/m ) or some
processing plants, laundries, effect of chlorides, e.g. urban areas,
breweries, dairies. coastal areas with low deposition of
chlorides.
Subtropical and tropical zone,
atmosphere with low pollution.
C4 High Spaces with high frequency of Temperate zone, atmospheric environ-
condensation and high pollution from ment with high pollution (SO : 30 µg/
3 3
production process, e.g. industrial m to 90 µg/m ) or substantial effect
processing plants, swimming pools. of chlorides, e.g. polluted urban areas,
industrial areas, coastal areas without
spray of salt water or, exposure to strong
effect of de-icing salts.
Subtropical and tropical zone,
atmosphere with medium pollution.
C5 Very high Spaces with very high frequency of Temperate and subtropical zone,
condensation and/or with high pollution atmospheric environment with very high
3 3
from production process, e.g. mines, pollution (SO : 90 µg/m to 250 µg/m )
caverns for industrial purposes, and/or significant effect of chlorides, e.g.
unventilated sheds in subtropical and industrial areas, coastal areas, sheltered
tropical zones. positions on coastline.
Table 1 (continued)
b
Typical environments — Examples
Corrosivity Corrosiv-
a
category ity
Indoor Outdoor
CX Extreme Spaces with almost permanent conden- Subtropical and tropical zone (very
sation or extensive periods of exposure high time of wetness), atmospheric
to extreme humidity effects and/or with environment with very high SO pollu-
high pollution from production process, tion (higher than 250 µg/m ) including
e.g. unventilated sheds in humid trop- accompanying and production factors
ical zones with penetration of outdoor and/or strong effect of chlorides, e.g.
pollution including airborne chlorides extreme industrial areas, coastal and
and corrosion-stimulating particulate offshore areas, occasional contact with
matter. salt spray.
NOTE 1 Deposition of chlorides in coastal areas is strongly dependent on the variables influencing the trans-
port inland of sea salt, such as wind direction, wind velocity, local topography, wind sheltering islands outside
the coast, distance of the site from the sea, etc.
NOTE 2 Extreme effect by chlorides, which is typical of marine splash or heavy salt spray, is outside of the
scope of this document.
NOTE 3 Corrosivity classification of specific service atmospheres, e.g. in chemical industries, is outside of the
scope of this document.
NOTE 4 Surfaces that are sheltered and not rain-washed in marine atmospheric environments where chlorides
are deposited and cumulated can experience a higher corrosivity category due to the presence of hygroscopic
salts.
NOTE 5 A detailed description of types of indoor environments within corrosivity categories C1 and C2 is given
in ISO 11844-1. Indoor corrosivity categories IC1 to IC5 are defined and classified.
NOTE 6  Source: ISO 9223:2012, Table C.1.
a
In environments with expected “CX category”, it is recommended that the atmospheric corrosivity classifica-
tion from one-year corrosion losses be determined.
b
The concentration of sulfur dioxide (SO ) should be determined during at least one year and is expressed as
the annual average.
Table 2 — UV categories (information only)
UV UV
Typical environments
category radiation
UV1 Low Solar radiation intensity is mild
UV2 Medium Solar radiation intensity is relatively strong
UV3 High Solar radiation intensity is very strong
7 Tests
7.1 General
The required properties and quality for the products should be chosen from the following testing
methods according to the agreement between the customer and the surface processor, before
application. Other test methods may be agreed between the customer and the surface processor.
The test specimens shall be cut from the significant surfaces of the products. However, if they cannot
be taken from the products, substitute test specimens produced together with the products may be
used for testing. The sampling lot size shall be agreed between the customer and the surface processor
considering the kind of products, size and quantity. Guidance on the choice of suitable sampling
procedures is given in ISO 2859-1.
In the absence of such an agreement, the size of test specimens shall be chosen from the following:
150 mm × 70 mm or 150 mm × 75 mm.
The surface of test specimens shall be wiped clean. For example, by using soft wet cloth with deionized
water or ethanol. Use deionized water for the coating attacked by ethanol.
Acceptance tests shall be specified by the customer.
In the absence of agreed procedures and for the resolution of disputes, the test methods given in this
clause shall be used.
Tests for production control purposes shall be at the discretion of the surface processor.
In cases where different requirements are not specified for individual corrosivity categories or UV
categories, the most demanding category should be applied.
7.2 Appearance
7.2.1 General
The coating shall be assessed by viewing from a distance of 5 m for parts used outside, of 3 m for parts
used inside and of 0,5 m for parts used for decoration. The observing angle shall be agreed between the
customer and the surface processor.
7.2.2 Measurement
Visual inspection shall be carried out under uniform artificial light or diffuse daylight in accordance
with ISO 4628-1. The lightness on the test specimens should be over 600 lx.
The reference sample shall be agreed between the customer and the surface processor.
7.2.3 Requirement
The coating shall be free from visible defects, such as excessive roughness, runs, blisters, inclusions,
craters, dull spots, pinholes, scratches or any damage breaking through to metal basis on the significant
surface.
The structure on the coating shall be distinct, have integrity and be uniform.
7.3 Colour
7.3.1 General
The colour of the coating shall be assessed by the visual method (see 7.3.2) or the instrumental method
(see 7.3.3).
7.3.2 Visual method
7.3.2.1 Measurement
The colour of the coating shall be assessed by viewing from a distance agreed between the customer
and the surface processor. Visual inspection shall be carried out under diffuse light, the source and
strength of which shall be agreed between the customer and the surface processor. The lightness on the
test specimens should be over 600 lx. Unless otherwise agreed, the colours shall be compared in diffuse
daylight from the direction of higher latitudes. If the coloured coatings are to be used in artificial light,
this lighting shall be used for colour comparison.
7.3.2.2 Requirement
Colour shall be judged using the standard colour samples which have been agreed between the customer
and the surface producer. Colour differences may also apply upper and lower reference samples to check
which have been agreed between the customer and the surface processor.
7.3.3 Instrumental method
7.3.3.1 Measurement
For instrumental colour measurement, measure the colour difference between the test specimen and
the reference sample by using a colour difference meter.
The colour may be measured by colourimetry in accordance with ISO/CIE 11664-1, ISO 11664-2,
ISO/CIE 11664-3, ISO/CIE 11664-4 and CIE 15. The customer and the surface processor should agree on
the measurement condition, including colorimetric system, illuminate, observation angle and geometric
light system.
7.3.3.2 Requirement
The colour tolerance shall be agreed between the customer and the surface processor.
This method does not apply to metallic paint finishes, textured coatings and embossed surfaces.
7.4 Gloss
7.4.1 General
The gloss of the coating shall be assessed by a visual method (see 7.4.2) an or instrumental method (see
7.4.3).
7.4.2 Visual method
7.4.2.1 Measurement
The gloss of coated articles shall be assessed by viewing from a distance agreed between the customer
and the surface processor.
Visual inspection shall be carried out under diffuse light, the source and strength of which shall be
agreed between the customer and the surface processor. The lightness on the test specimens should be
over 600 lx. Unless otherwise agreed, the gloss shall be compared in diffuse daylight from the direction
of higher latitudes. If the coloured coatings are to be used in artificial light, this lighting shall be used
for gloss comparison.
7.4.2.2 Requirement
Gloss shall be judged using the standard gloss samples which have been agreed between the customer
and the surface processor.
7.4.3 Instrumental method
7.4.3.1 Measurement
Th
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