ISO 787 General Test Methods for Pigments and Extenders

The "ISO 787 General test methods for pigments and extenders" standard, published by the International Organization for Standardization (ISO), consists of the following sub-sections published under the same title:

The standard “ISO 787-1 Part 1: Color Comparison of Pigments” describes a general test method for comparing the color of a colored pigment to the color of an agreed-upon sample. Any of the described procedures are acceptable, but the method using an automated Müller is the reference method. Where this general method is applicable to a specific pigment, a cross-reference to the international standard for that pigment should be added, along with a note detailing any necessary modifications considering the specific properties of the material. Only when the procedures given in this general method are not applicable to a specific material should a specific method for color comparison be specified.
The standard “ISO 787-2 Part 2: Determination of volatile matter at 105 degrees” describes a general test method for determining the mass fraction of volatile matter in a pigment or filler sample at 105 degrees Celsius as a percentage. This method is applicable to pigments and fillers that are stable at 105 degrees Celsius.
The standard “ISO 787-3 Part 3: Determination of water-soluble substance - Hot extraction method” describes a general test method for determining the percentage by mass of water-soluble substance in a pigment or filler sample. ISO 787-8 specifies a method for determining the percentage by mass of water-soluble substance by cold extraction. For most pigments and fillers, these two test methods yield different results, and therefore it is important that which method is used and which method was used is clearly stated in the specification and test report.
The standard “ISO 787-4 Part 4: Determination of the acidity or alkalinity of an aqueous extract” describes a general test method for determining the acidity or alkalinity of an aqueous extract of a pigment or extender sample.
ISO 787-5 Part 5: Determination of oil absorption value describes a general test method for determining the oil absorption value of a pigment or filler sample. The oil absorption value should generally be compared to a value determined on a product sample agreed upon at the same time.
The standard “ISO 787-7 Part 7: Determination of residue on sieve - Water method - Manual procedure” describes a general test method for determining residue on a sieve from a sample of pigment or filler dispersed in water. The ISO 787-18 standard includes a general test method for determining residue on a sieve from a sample of pigment or filler by a mechanical washing procedure. For most pigments and fillers, the ISO 787-7 and ISO 787-18 standards often yield different results, and therefore it is important that the specification clearly states which method is used and which method is indicated in the test report.
The standard “ISO 787-8 Part 8: Determination of water-soluble substance - Cold extraction method” describes a general test method for determining the mass percentage of water-soluble substance in a pigment or filler sample using cold extraction. The ISO 787-3 standard includes a method for determining the mass percentage of water-soluble substance by hot extraction. For most pigments and fillers, these two test methods yield different results, and therefore it is important that which method is used and which method was used is clearly stated in the specification and test report.
ISO 787-9 Part 9: Determination of pH of an Aqueous Suspension describes a general test method for determining the pH of an aqueous suspension of a pigment or extender sample.
The standard “ISO 787-10 Part 10: Determination of Density - Pycnometer Method” describes general test methods for determining the density of a pigment or extender sample using a pycnometer. ISO 787-23 specifies a general method using centrifugation to remove trapped air.
The standard “ISO 787-11 Part 11: Determination of compressed volume and apparent density after compression” describes a general test method for determining the compressed volume and apparent density after compression of a pigment or extender sample.
ISO 787-13 Part 13: Determination of water-soluble sulfates, chlorides and nitrates” standard describes a general test method for determining water-soluble sulfates, chlorides and nitrates of pigments.
The standard “ISO 787-14 Part 14: Determination of the Resistivity of Aqueous Extracts” describes a general test method for determining the electrical resistivity (specific electrical resistance) or specific electrical conductivity, respectively, of an aqueous extract of a pigment. This method is applicable to all pigments and fillers except those that are water-soluble. The resistivity of an aqueous extract of a pigment is considered a property independent of the amount of water-soluble substance. If agreed upon, the cold extraction method may be used.
ISO 787-15 Part 15: Comparison of the light resistance of similar types of colored pigments describes a general test method for comparing the light resistance of similar types of colored pigment samples (agreed reference pigment and test sample). This standard describes two exposure methods. In method A, the material is exposed to natural light under glass. In method B, the material is exposed directly to artificial light.
The standard “ISO 787-16 Part 16: Determination of relative coloring power (or equivalent color value) and color by reduction of colored pigments - Visual comparison method” describes a general test method for comparing the coloring power and color obtained by reducing two similar colored pigments. The results are expressed as “relative coloring power” or “equivalent color value”. The ISO 787-24 standard includes a general test method for determining the relative coloring power of colored pigments using a photometric method.
The standard “ISO 787-17 Part 17: Comparison of the illuminating power of white pigments” describes a general test method for comparing the illuminating power of a white pigment to that of an agreed-upon sample of the same type. This standard includes two procedures (A and B). Procedure A is faster than Procedure B and is suitable for testing a single pigment sample. Procedure B is better for testing several samples, especially if a pigment with unknown illuminating power is being tested.
The standard “ISO 787-18 Part 18: Determination of residue on sieve - Mechanical washing procedure” describes a general method for determining residue on a sieve from a pigment or filler sample dispersed in water using a mechanical washing procedure. This method can also be used to examine other powders or granules that are insoluble in water. It is not applicable to hydrophobic or pelletized pigments and fillers. The ISO 787-7 standard includes a general test method for determining residue on a sieve from a pigment or filler sample dispersed in water using a manual procedure. For most pigments and fillers, these two test methods yield different results, and therefore, it is important to clearly state which method was used and which method was used in the test report.
The standard “ISO 787-19 Part 19: Determination of water-soluble nitrates (salicylic acid method)” describes a general test method for determining water-soluble nitrates in a pigment sample by spectrophotometric method using salicylic acid. ISO 787-13 includes a method for determining water-soluble nitrates in a pigment sample using the Nessler method.
The standard “ISO 787-20 Part 20: Comparison of ease of dispersion (oscillatory shaking method)” describes a general test method for comparing the ease of dispersion of two similar pigments in a given medium. The result is expressed in terms of the shaking time required to achieve the specified grinding fineness in a particular device. This method is most likely to be indicative of the comparative results that would be obtained when the pigments being compared are ground in a resin solution in specific types of mills, e.g., a ball mill.
ISO 787-21 Part 21: Comparison of the heat stability of pigments using baking media describes a general test method for comparing the heat stability of a pigment under test with that of an agreed-upon sample.
The standard “ISO 787-22 Part 22: Comparison of the bleeding resistance of pigments” describes a general method for comparing the bleeding resistance of a pigment against that of an agreed-upon sample.
The standard “ISO 787-23 Part 23: Determination of density (by centrifugation and removal of air)” specifies a general test method for determining the density of a pigment or filler sample by removing air using centrifugation. This standard includes a general test method for determining the density of a pigment or filler sample using a pycnometer.
The standard “ISO 787-24 Part 24: Determination of the relative coloring power of colored pigments and the relative scattering power of white pigments - Photometric methods” describes photometric test methods for comparison in the visible spectrum:
The coloring strength of two similarly colored pigments dispersed in an alkyd resin without a desiccant.
The scattering power of two white pigments of the same type dispersed in an alkyd resin without a desiccant.

These test methods offer an instrumental alternative to those described in ISO 787-16 and ISO 787-17, respectively, by eliminating the need for visual matching. This standard is not suitable for comparing colored pigments whose color changes significantly when reduced.

The standard “ISO 787-25 Part 25: Comparison of the colors of white, black and colored pigments in full shade systems - Colorimetric method” describes a general test method for comparing the color of white, black or colored pigments in full shade systems to the color of an agreed reference pigment using a colorimetric procedure.
The standard “ISO 787-26 Part 26: Determination of relative coloring power and permanent color difference of colorings - Weighted K/S value method” describes a method for determining the relative coloring power of colorings and the permanent color difference between a test coloring and a reference coloring, when the coloring power criterion values are the same. This method is suitable for testing colorings reduced with a white pigment in textiles, paper, solutions, transparent coating materials or printing inks on a white substrate, provided that the relevant theories are used. Calculations are performed only for systems where the Kubelka-Munk theory is applicable.
The standard “ISO 787-27 Part 27: Determination of relative coloring power (or equivalent color value) and color by reduction of colored pigments - Visual comparison method” describes a visual comparison method for determining two basic properties of colored pigments (relative coloring power (also called equivalent color value)).
How strongly a pigment colors a white base (usually a full tone or a deep tone). Color in reduction (coloring or lightening tone).
The appearance of color when the pigment is strongly reduced (increased) by a large amount of white pigment.

These methods are a classic and traditional approach used for quality control and color matching in the pigment, dye, coating, plastics, and printing ink industries where instrumental methods (e.g., spectrophotometry) are not required or visual evaluation is preferred.

The standard “ISO 787-28 Part 28: Determination of total content of polychlorinated biphenyls (PCBs) by dissolution, purging and GC-MS” describes a method for determining the total content of polychlorinated biphenyls (PCBs) in pigment materials by checking all 209 possible congeners. This standard is valid for a working range between 1 mg/kg and 150 mg/kg. The lower quantification limit of this method is 1 mg/kg per congener. Results below 1 mg/kg are considered qualitative only.
The standard “ISO 787-29 Part 29: Determination of resistance to liquids” is under development. This standard includes general test methods for determining the resistance of pigments to water, acid, alkali, and solvents.
The standard “ISO 787-30 Part 30: Determination of the illuminating power of white pigments - Visual comparison method” describes a visual comparison method for determining the illuminating power (also called reducing power or coloring power) of white pigments (primarily titanium dioxide rutile and anatase, but also zinc sulfide, lithopone, etc.). This method measures how effectively a white pigment illuminates a colored paste (usually a black or colored pigment paste) when mixed in small amounts. This standard is the visual equivalent of the instrumental method (using spectrophotometry) described in ISO 787-24.
The standard “ISO 787-31 Part 31: Determination of the illuminating power of white pigments - Instrumental method (colorimetric method using reflectance measurements)” describes a method for instrumentally (spectrophotometrically) determining the coloring power/lightening power/reducing power of white pigments (especially titanium dioxide) by measuring how much they illuminate a black paste.
The standard “ISO 787-32 Part 32: Determination of the color of pigmented pastes by grayscale method (visual comparison)” describes a visual method for evaluating subtle color differences between two pigmented pastes (usually full tone or intense tone) using the standardized ISO grayscale (the same 5-step scale known from color fastness testing) to assess color variation.

Consequently, the ISO 787 series of standards provides a global basis for testing pigments and fillers. Almost every pigment data sheet, technical specification, contract, and quality control laboratory worldwide refers to one or more sections of this standard.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "ISO 787 General test methods for pigments and extenders" standard.