EN ISO 787-24:1995

General method of tests for pigments and extenders - Part 24: Determination of relative tinting strength of coloured pigments and relative scattering power of white pigments - Photometric methods (ISO 787-24:1985)

The method specified provide an instrumental alternative to those described in ISO 787/16 and ISO 787/17. Equal masses of a coloured material are separately dispersed in the same mass of the same white pigment paste. The reflectivity of each dispersion is measured photometrically. From the corresponding values of K/S the relative tinting strength is given. For measurement of the relative scattering power equal masses of a white test material and an agreed reference pigment are separately dispersed in the same mass of the same black pigment paste. The reflectivity of each dispersion is measured photometrically at 550 nm. From the corresponding values of K/S the relative scattering power is given.

Allgemeine Prüfverfahren für Pigmente und Füllstoffe - Teil 24: Bestimmung der relativen Farbstärke von Buntpigmenten und des relativen Streuvermögens von Weißpigmenten - Photometrische Verfahren (ISO 787-24:1985)

Dieser Teil von ISO 787 beschreibt photometrische Prüfverfahren zum Vergleich a) der Farbstärke zweier ähnlicher Buntpigmente (siehe Anmerkung 1), die ohne Trockenstoffzusatz in einem Alkydharz dispergiert sind und; b) des Streuvermögens zweier Weißpigmente des gleichen Typs, die ohne Trockenstoffzusatz in einem Alkydharz dispegiert sind, im sichtbaren Spektralbereich. Diese Prüfverfahren stellen eine meßtechnische Alternative zuden in ISO 787-16 und ISO 787-17 beschriebenen Verfahren dar, wobei der visuelleVergleich enfällt.

Méthodes générales d'essai des pigments et matières de charge - Partie 24: Détermination du pouvoir colorant relatif des pigments colorés et du pouvoir diffusant relatif des pigments blancs - Méthodes photométriques (ISO 787-24:1985)

La présente partie de l'ISO 787 décrit des méthodes photométriques
  d'essai pour comparer dans la partie visible du spectre :
a) le pouvoir colorant de deux pigments colorés similaires (voir note
  1) dispersés dans une résine alkyde sans siccatif;
b) le pouvoir diffusant de deux pigments blancs du même type dispersés
  dans une résine alkyde sans siccatif.
Ces méthodes d'essai fournissent une mesure instrumentale en complément
  des méthodes respectivement décrites dans les parties 16 et 17
  de l'ISO 787, évitant la nécessité d'un contrôle
  visuel.
  NOTES:
  1) La présente Norme internationale ne convient pas pour la comparaison
  de pigments colorés dont la couleur en dégradé présente
  d'importants écarts.
  2) Chaque fois que l'une de ces méthodes générales est
  applicable pour un pigment donné, il devra simplement être fait
  référence à la méthode appropriée dans la
  Norme internationale relative à ce pigment, en indiquant, dans une note,
  toutes les modifications de dé

Splošne metode preskušanja pigmentov in polnil - 24. del: Določanje relativne barvne jakosti barvastih pigmentov in relativne moči sipanja belih pigmentov - Fotometrične metode (ISO 787-24:1985)

General Information

• Status: Published
• Publication Date: 22-Aug-1995
• Withdrawal Date: 28-Feb-1996
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: CEN/TC 298 - Pigments and extenders
• Drafting Committee: CEN/TC 298 - Pigments and extenders
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 07-Dec-2007
• Completion Date: 07-Dec-2007
• Ref Project: SIST EN ISO 787-24:1997 - General method of tests for pigments and extenders - Part 24: Determination of relative tinting strength of coloured pigments and relative scattering power of white pigments - Photometric methods (ISO 787-24:1985)

Relations

• Revised: prEN ISO 787-24 - General methods of test for pigments and extenders - Part 24: Determination of relative tinting strength of coloured pigments and relative scattering power of white pigments - Photometric methods (ISO/DIS 787-24:2025)
• Effective Date: 08-Nov-2023

Overview

EN ISO 787-24:1995 (ISO 787/24:1985) specifies photometric test methods for comparing the tinting strength of coloured pigments and the scattering (opacity) power of white pigments. It provides an instrumental alternative to the visual procedures in ISO 787-16 and ISO 787-17 by measuring reflectivity and calculating K/S (Kubelka–Munk) values. The method gives relative tinting strength for coloured pigments and relative scattering power for white pigments, enabling objective, repeatable pigment performance comparisons.

Key topics and technical requirements

• Principle: Prepare dispersions of equal masses of test and reference pigments in a consistent paste, measure reflectivity, then compute K/S ratios to give relative tinting or scattering values.
• Coloured pigments: Test pigment and agreed reference pigment are each dispersed in the same white pigment paste; reflectivity measured photometrically across visible wavelengths; K/S ratios used to compute relative tinting strength.
• White pigments: Test pigment and agreed reference pigment are each dispersed in the same black pigment paste; reflectivity measured at 550 nm (or using a Y-filter); K/S ratios give relative scattering power (expressed as a percentage).
• Optical model: Uses Kubelka–Munk analysis (K = absorption, S = scattering) and reflectance-to-K/S conversion to quantify colouring and scattering effects.
• Sample preparation & materials: Specifies preparation of white and black pigment pastes (examples include titanium dioxide-based white paste and carbon-black-based black paste), use of an alkyd resin binder, and grinding/dispersion procedures.
• Apparatus: Spectrophotometer (400–700 nm) or tristimulus calorimeter, triple-roll mill, automatic muller (ground glass plates), paste film holders/drawdowns and fineness-of-grind control.
• Reporting: Method variants and any deviations must be documented in the test report; when multiple accepted procedures exist, the chosen method should be stated.

Applications and who uses it

• Paint, coatings and ink manufacturers use EN ISO 787-24 for product development, QC and batch-to-batch consistency checks of pigments and extenders.
• Pigment producers and raw‑materials labs apply the method to characterize and certify tinting strength and opacity compared with agreed references.
• Quality assurance and R&D teams use photometric methods to replace subjective visual matching, enabling faster and more reproducible pigment evaluations.
• Suppliers and standards bodies reference the standard in pigment specifications and supplier declarations.

Related standards

• ISO 787 series (general methods for pigments and extenders) - notably Part 16 (visual tinting strength) and Part 17 (lightening power of white pigments)
• ISO 591 (titanium dioxide test methods), ISO 1524 (fineness of grind), ISO 4652 (carbon black surface area)
• Kubelka–Munk theory referenced for K/S calculations

Keywords: EN ISO 787-24, ISO 787/24, tinting strength, scattering power, pigments, extenders, photometric methods, K/S, spectrophotometer, paint testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-1997
6SORãQHPHWRGHSUHVNXãDQMDSLJPHQWRYLQSROQLOGHO'RORþDQMHUHODWLYQH
EDUYQHMDNRVWLEDUYDVWLKSLJPHQWRYLQUHODWLYQHPRþLVLSDQMDEHOLKSLJPHQWRY
)RWRPHWULþQHPHWRGH,62
General method of tests for pigments and extenders - Part 24: Determination of relative
tinting strength of coloured pigments and relative scattering power of white pigments -
Photometric methods (ISO 787-24:1985)
Allgemeine Prüfverfahren für Pigmente und Füllstoffe - Teil 24: Bestimmung der relativen
Farbstärke von Buntpigmenten und des relativen Streuvermögens von Weißpigmenten -
Photometrische Verfahren (ISO 787-24:1985)
Méthodes générales d'essai des pigments et matieres de charge - Partie 24:
Détermination du pouvoir colorant relatif des pigments colorés et du pouvoir diffusant
relatif des pigments blancs - Méthodes photométriques (ISO 787-24:1985)
Ta slovenski standard je istoveten z: EN ISO 787-24:1995
ICS:
87.060.10 Pigmenti in polnila Pigments and extenders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

International Standard 787124
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.ME~fiYHAPOfiHAR OPTAHM3A~Mfl IlO CTAH~APTbl3A~Mi4.ORGANISATION INTERNATIONALE DE NORMALlSATlOh
General methods of test for pigments and extenders -
Part 24 : Determination of relative tinting strength of
coloured pigments and relative scattering power of white
pigments -
Photometric methods
Mkthodes g&-&ales d’essai des pigments et mat&es de charge - Partie 24 : Dktermina tion du oouvoir colorant rela tif des
pigments color& et du pouvoir diffusant relatif des pigments blancs - Mkthodes ,ohotom&ic&s
Second edition - 1985-12-15
UDC 667.622 : 535.24 : 535.362
Ref. No. IS0 787/24-1985 (E)
Descriptors : paints, pigments, tests, determination, colouring power, photometric method.
- Price based on 11 pages
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 787/24 was prepared by Technical Committee ISO/TC 35,
Paints and varnishes.
This second edition cancels and replaces the first edition (IS0 787/24-1982), of which
it constitutes a minor revision.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
International Organization for Standardization, 1985
Printed in Switzerland
ii
The purpose of this International Standard is to establish a series of general test
methods for pigments and extenders which are suitable for all or many of the individual
pigments and extenders for which specifications might be required. In such cases, a
cross-reference to the general method should be included in the International Standard
relating to that pigment or extender, with a note of any detailed modification which
might be needed in view of the special properties of the product in question.
Technical Committee ISO/TC 35, Paints and varnishes, decided that all the general
methods should be published as they become available, as parts of a single lnterna-
tional Standard, in order to emphasize the relationship of each to the whole series.
The Technical Committee also decided that, where two or more procedures were wide-
ly used for determining the same or a similar characteristic of a pigment or extender,
there would be no objection to including more than one of them in the IS0 series. In
such cases it will, however, be essential to state clearly in a specification which method
is to be used and, in the test report, which method has been used.
Parts of the series already published are as follows :
Part 1 : Comparison of colour of pigments
Part 2 : Determination of matter volatile at 105 OC
Part 3 : Determination of matter soluble in water - Hot extraction method
Part 4 : Determination of acidity or alkalinity of the aqueous extract
: Determination of oil absorption value
Part 5
Part 7 : Determination of residue on sieve - Water method - Manual procedure
Part 8 : Determination of matter soluble in water - Cold extraction method
Part 9 : Determination of pH value of an aqueous suspension
Part 10 : Determination of density - Pyknometer method
Part 11 : Determination of tamped volume and apparent density after tamping
Part 13 : Determination of water-soluble sulfates, chlorides and nitrates
Part 14 : Determination of resistivity of aqueous extract
Part 15 : Comparison of resistance to light of coloured pigments of similar types
Part 16 : Determination of relative tinting strength (or equivalent colouring value)
and colour on reduction of coloured pigments - Visual comparison method
Part 17 : Comparison of lightening power of white pigments
Part 18 : Determination of residue on sieve - Water method - Mechanical
flushing procedure
Part 19 : Determination of water-soluble nitrates - Salicylic acid method
Part 20 : Comparison of ease of dispersion - Oscillatory shaking method
Part 21 : Comparison of heat stability of pigments using a stoving medium
Part 22 : Comparison of resistance to bleeding of pigments
Part 23 : Determination of density (using a centrifuge to remove entrained air)
Part 24 : Determination of relative tinting strength of coloured pigments and
relative scattering power of white pigments - Photometric methods

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INTERNATIONAL STANDARD IS0 787/24-1985 (E)
General methods of test for pigments and extenders -
Part 24 : Determination of relative tinting strength of
coloured pigments and relative scattering power of white
pigments - Photometric methods
IS0 787, General methods of test for pigments and extenders -
0 Introduction
Part 2 : Determination of matter volatile at 105 OC.
This document is a part of IS0 787, Genera/methods of test for
pigments and extenders.
Part 9 : Determination of ,oH value of an aqueous
suspension.
Part 70 .= Determination of density - Pyknometer method.
1 Scope and field of application
Part 76 : Determination of relative tinting strength (or
This part of IS0 787 describes photometric methods of test for equivalent colouring value) and co/our on reduction of
comparing in the visible spectrum coloured pigments - Visual comparison method.
Part 77 : Comparison of lightening power of white
a) the tinting strength of two similar (see note 1) coloured
pigments.
pigments dispersed in an alkyd resin without a drier;
Part 23 : Determination of density (using a centrifuge to
b) the scattering power of two white pigments of the
remove en trained air).
same type dispersed in an alkyd resin without a drier.
IS0 842, Raw materials for paints and varnishes - Samolinq.
, .
These methods of test provide an instrumental alternative to
IS0 1524, Paints and varnishes - Determination of fineness of
those described in IS0 787/16 and IS0 787/17 respectively,
grind.
avoiding the necessity of visual matching.
IS0 3219, Plastics - Polymers in the liquid, emulsified or
NOTES
Determination of viscosity with a rotational
dispersed state -
1 This International Standard is not appropriate for the comparison of viscometer working at defined shear rate.
coloured pigments that on reduction differ greatly in colour.
IS0 3262, Extenders for paints.
2 When one of these general methods is applicable to a given
pigment, only a cross-reference to the appropriate method should be
IS0 3682, Binders for paints and varnishes - Determination of
included in the International Standard relating to that pigment,
Titrime tric method.
acid value -
indicating any detailed modification which may be needed in view of
the special properties of the product in question. Only when the
appropriate method in this part of IS0 787 is not applicable to a IS0 4629, Binders for paints and varnishes - Determination of
particular product should different photometric methods for
hydroxyl value - Titrime tric method. 1)
determination of relative tinting strength and determination of relative
scattering power be specified.
IS0 4652, Rubber comoounding ingredients - Carbon black
, I
- Determination of specific surface area - Afitrogen
adsoro tion methods.
2 References
IS0 6209, Rubber compounding ingredients - Carbon black
I SO 591, Titanium dioxide pigments for paints. - Determination of solvent extractable material.
-I__-- -.
I) In course of preparation. (Revision of IS0 4629-1978.)
IS0 787/24-1985 (El
32.3 scattering index S,(A) : The spectral scattering co-
3 Definitions
efficient of the pigmented binder divided by the pigment
concentration C, (see 3.1.3) :
For coloured and black pigments
3.1
SW
s,(a) = --- . . . (3)
3.1 .I tinting strength : The ability of a pigment (see the
c,
note) to absorb incident light, thereby having the power to
colour or darken, for example, a white paint in which it is incor-
3.2.4 relative scattering power S,[;1) : The ratio of the scat-
porated.
tering index of the test sample S&) to that of an agreed
reference pigment SD4(A), expressed as a percentage :
NOTE - Although the properties tested are strictly those of the
pigmented binder, absorption and scattering by the binder are rela-
sp3fa)
tively small and it is assumed in this International Standard that the
s,(a) = --- x 100 . . .
(4)
material under test is the dispersed pigment.
sp4( a I
3.3 reflectivity cco : The reflectance of a paste or a paint
3.1.2 spectral absorption coefficient K(A) : The fraction of
film of such thickness that further increase in thickness gives
the diffusely incident spectral radiant flux of wavelength A that
no further change in reflectance.
is absorbed in an elementary layer within a material, divided by
the thickness of the layer (Kubelka-Munk analysis).
according to equation (lo), is
The reflec tivity ,o”,, corrected
related to K/S by the equation
NOTE - KU ) is a measure of the tinting strength of coloured pigmen
in a material and is expressed in units of reciprocal film thickness.
K (1 -&J2
_.-. -.-.-.
. . . (5)
s= 2_0”,
3.1.3 absorbance index K,(1) : The spectral absorption
coefficient of the pigmented binder divided by the pigment
Values of K/S as a function of 100 Q* or 100 R, are given in
concentration C, :
annex B.
NOTES
iv(a)
. . . (I)
1 Kubelka-Munk analysis is strictly applicable only to monochromatic
Kp(a) = c--
n-l
radiation, as indicated in equations (I) to (4). In practice, however, cor-
rect results are often also obtained if the mean value for wider
where C, is the pigment
concentration, for example, ex-
wavebands is taken, as is the case when filters are used. Hence, in the
pressed as the ratio by mass of pigment to binder.
subsequent equations the symbol 3, is omitted.
2 In a dispersion containing a coloured or black pigment and a white
pigment, K is assumed to be characteristic of the coloured or black
3.1.4 relative tinting strength K,(A) : The ratio of the ab-
pigment and S of the white pigment.
sorbance index of the test sample K,t(A) to that of an agreed
reference pigment Kp2(AI, expressed as a percentage :
: The ratio of the radiant flux
3.4 reflectance factor R,
reflected in the directions within a given cone by a paste or a
K,,(A)
K,(A) = -. x 100
. . . (2)
paint film to that reflected in the same directions by a perfect
Kp2( a 1
reflecting diffuser identically irradiated, when the thickness of
the paste or the paint film is such that further increase in
thickness gives no further change in the ratio.
3.2 For white pigments
3.2.1 scattering power : 4 Principle
The ability of a pigment (see the
note to 3.1 .l) to diffuse incident light, thereby having the
power to confer opacity and lightness to, for example, a paint
4.1 Coloured and black pigments
in which it is incorporated.
Equal masses of a coloured pigment p1 and of an agreed
reference pigment p2 are separately dispersed in the same mass
3.2.2 spectral scattering coefficient S(A) : The net transfer
of the same white pigment paste. The reflectivity e,co or the
of spectral radiant flux of wavelength ;1 in the outward direction
reflectance factor R, of each dispersion is measured
from an elementary layer within a body of material illuminated
photometrically at a wavelength giving a minimum value of p_o,
from outside, divided by the product of the thickness of the
or R,. From the corresponding values of K/S, the relative
layer and the difference between the magnitude of the flux in
tinting strength, K,, of the test pigment is given by the equation
the two directions through the layer (Kubelka-Munk analysis).
(Kp,M
KPl
NOTE - Y( 1 ) is a measure of the scattering power of white pigme nts K,= . . .- x lo(-) = -.-. X I()()
. . . (6)
K
in a materia and is expressed in units of reciprocal film thickness. (K,,/S)
P2
IS0 787/24-1985 (El
NOTES
1 The black pigment paste is available commercially. The mixture
K,,/S is the K/S value corresponding to Q~ or R, of the
specified in 5.2.2 is suitable for testing at a pigment volume concen-
test pigment;
tration of 17 % .
K&S is the K/S value corresponding to ~~ or R, of the 2 Carbon black pigment of the lampblack complying with the
type
following requirements :
agreed reference pigment.
Test method
4.2 White pigments
nigrometer index value 102
volatile matter content about 1 % IS0 78712
Equal masses of a white test pigment p3 and of an agreed 0,15 % max. IS0 6209
toluene extractable matter
specific surface area (BET) 20 m*/g IS0 4652
reference pigment p4 are separately dispersed in the same mass
pH value 7 IS0 787/9
of the same black pigment paste. The reflectivity coo or the
reflectance factor R oo of each dispersion is measured
3 Alkyd resin, based on a mixture of 63 % (IV/VI) linseed oil and
photometrically at 550 nm or using a Y-filter. From the cor-
23 % (IV/M) phthalic anhydride, and complying with the following
responding values of K/S, the relative scattering power, S,, of
requirements :
the test pigment, is given by the equation
Test method
S 15 mg KOH/g
s _ (K&4) acid value
-@x 100 . . .
(7)
max. IS0 3682
r - (K/S,3) x ‘O” = sp4
viscosity (solvent free) 7 to 10 Pas IS0 3219
hydroxyl content about
40 mg KOH/g IS0 4629
This alkyd resin is commercially available.
is the K/S value corresponding to coo or R, of the
q3
test pigment;
4 Fumed silica complying with the following requirements :
is the K/S value corresponding to pco or R, of the
Test method
K/S,4
agreed reference pigment.
specific surface area (BET) 175 to 225 m*/g
pH value of a 4 %
dispersion in water 3,6 to 4,5 IS0 787/9
5 Materials and equipment
6 Apparatus
5.1 White pigment paste, with the following composition
6.1 Triple-roll mill.
- 40 parts by mass of titanium dioxide, Grade R2, com-
plying with the requirements of IS0 591;
6.2 Automatic muller, with ground glass plates, preferably
water cooled (see the note), -of diameter 180 to 250 mm to
56 parts by mass of alkyd resin (see note 3 to 5.2);
which a variable but known force of up to about 1 kN may be
applied. The driven glass plate should have a speed of rotation
4 parts by mass of calcium stearate.
of between 70 and 120 r/min and the apparatus should have an
arrangement for pre-setting the number of revolutions in
Using a spatula, mix well so as to preliminary wetting
multiples of 25.
of the solids.
Pre-condition new muller plates by milling a pigment in a
Then grind on the triple-roll mill (6.1) until the particle size is
suitable binder (system) for 1 000 revolutions with a load
less than 5 pm when tested on a fineness-of-grind gauge (see
applied to the plates. Remove the paste and discard.
IS0 1524). Store the paste in an airtight container, preferably a
collapsible tube with a screw cap.
Before use, check the surface of both plates for freedom from
score marks, freedom from polished areas and for an even
.
opaque appearance.
Black pigment paste (see note I), prepared as follows.
5.2
NOTE - If the automatic muller does not have water-cooled plates,
5.2.1 Mix 18,7 parts by mass of carbon black pigment (see
take care that the temperature during the grinding operation does not
note 2) with 81,3 parts by mass of alkyd resin (see note 3) by
rise by more than IO OC.
use of a spatula. Pass the mixture six times through the triple-
roll mill (6.1) to achieve a uniform fine dispersion.
6.3 Paste film holders, for example a suitable dish, for each
test dispersion to support a paste film of about 250 pm
5.2.2 Mix 3,25 g of the intermediate paste prepared as
thickness; it may have a spacing ring.
described in 5.2.1 with 9164 g of alkyd resin (see note 3) and
5,11 g of fumed silica (see note 4); pass the mixture once that is sufficiently
NOTE - Alternatives are to prepare a drawdown
thick to be completely opaque and to cover this with a template so that
through the triple-roll mill.
IS0 787/24-1985 (El
NOTE - A different mass of the coloured pigment or another method
an area corresponding to the sample port of the photometer is ex-
of dispersion (for example see IS0 787/16 clause 8) may be used by
posed, or to prepare an opaque drawdown on a glass plate and
measure through the glass. agreement between the interested parties, but should be stated in the
test report.
6.4 Spectrophotometer capable of measuring at
8.1.3 Preparation of test films
wavelengths between 400 and 700 nm or a tristimulus
calorimeter with illuminant D,,.
Place the test pigment dispersion (8.1 .I ) and the reference pig-
ment dispersion (8.1.2) in the paste film holders (6.3), ensuring
If a tristimulus calorimeter is used, appropriate filters are
that the exposed surface is uniform and level.
required for the coloured pigments under test, and a CIE Y-filter
for the testing of white pigments.
8.1.4 Measurement of 90, or R,
NOTE - For certain purposes, it is sometimes informative to compare
the scattering power of white pigments at other wavelengths; by
Measure Q~ or R, of each film with the photometer (see 6.4).
agreement between the interested parties the tristimulus values X or Z
Both measuring geometries including and excluding gloss are
or the spectral reflectance or the reflectance factor at an agreed
suitable.
wavelength may be measured and used for the calculation of the
relative scattering power.
If a spectrophotometer is used, vary the wavelength of light
entering the photometer between 400 and 700 nm until a
minimum value of Q~ or R, is obtained (at the wavelength of
7 Sampling
maximum absorption) and record the value of pco or R, at that
wavelength for each film.
Take a re presentative
sample of the product to be tested as
described in IS0 842.
If a tristimulus calorimeter is used, select a filter that restricts
the measurements to wavelengths close to that of maximum
absorption. Note the reading given by the calorimeter and
8 Procedure
divide it by 100 to obtain the value of ,o, or R,.
8.1 Determination of relative tinting strength
82 . Determination of relative scattering power
8.1 .I Test pigment dispersion
NOTE - According to the procedure described in 8.2.1 to 8.2.4 a pig-
ment volume concentration of 17 % is chosen. This concentration is
Weigh 3 _+ 0,Ol g of the white pigment paste (5.1) and 0,12 g
preferred because in practice the white pigment volume concentration
of the test sample. Place the white pigment paste in the centre of many air-drying paints is between 15 and 20 %.
of the lower plate of the automatic muller (6.2). Sprinkle the
test sample on to the white pigment paste and mix together,
8.2.1 Test pigment dispersion
using the minimum of effort with the aid of a spatula. Distribute
the paste at several points at a distance of about 35 mm from
Take a quantity of the white test sample, such that
the centre of the lower plate or spread within a ring with an
internal diameter of 40 mm and an
...