ISO 18314-2-2015 Analytical colorimetric method — Part 2: Saunderson correction, solution to the Kubelka-Munk equation, coloring power, covering power

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The second edition cancelled and replaced the first edition (ISO 18314-2:215), which had been technically revised.

The main changes are as follows:

– The title has been changed to “Shadow Depth”;

— The terms and definitions in Article 3 are consistent with ISO 18451-1;

— The documents have been edited and revised, and the bibliography has been updated.

A list of all the parts in the ISO 18314 family can be found on the ISO website.

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ISO 18314-2-2015 Analytical colorimetric method — Part 2: Saunderson correction, solution to the Kubelka-Munk equation, coloring power, covering power

1 range
This document specifies Sanderson corrections for different measurement geometers and solutions to the Kubelka-Munk equations for hidden and transparent layers. It also specifies ways to calculate shading intensity based on different criteria, such as shadow depth, including residual chromatic aberration. Finally, the method to determine the covering power is given.

Procedures for preparing samples for these measurements are not part of this document. They are agreed upon by the Parties or described in other national or international standards.

2 Normative references
There is no normative reference in this document.

3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.

3.1 Coloring power

Color intensity

A measure of the colorant’s ability to color other materials because of its absorption capacity

[Source: ISO 18451-1:2019, 3.122]

3.2 Relative coloring power

Relative color intensity

The percentage ratio of the coloring strength of the colorant under test (3.1) to the coloring strength of the reference colorant

[Source: ISO 18451-1:2019, 3.105]

3.3 Coloring strength standard

A parameter that describes the coloring effect of a colorant based on its absorption

Note 1: The coloring strength standards used in this document are as follows:

— the value of Kubelka-Munk function at the maximum absorption;

— Weighted sum of Kubelka-Munk function values;

— trististimulus value Y;

— the smallest of the three stimulus values X, Y and Z;

– Shadow depth parameter B.

Note 2: Examples of other coloring strength parameters not used in this document are as follows:

— Unweighted sum of Kubelka-Munk function values;

— Chroma consists of three color coordinates (L*, a*, b*);

— Reflection coefficient at maximum absorption.

3.4 Residual color difference

When the tint intensity criterion (3.3) values are the same or equalized, the color difference that still exists between the reference sample and the test sample decreases in whiteness

Example: Residual color difference is given by ΔE*.

3.5 Shadow Depth

Color depth

Measure the intensity of color perception that increases as chroma increases and decreases as brightness increases

Note 1: Colorants with the same shadow depth appear to have been prepared using colorants of the same concentration with the same coloring strength (3.1).

[Source: ISO 18451-1:2019, 3.26, modified – The accepted terms “shadow depth” and “color depth” have been added.

ISO 18314-2-2015 Analytical colorimetric method — Part 2: Saunderson correction, solution to the Kubelka-Munk equation, coloring power, covering power

3.6 Standard Shadow depth

Standard shadow depth

Standard color depth

Standard clear

Conventionally specified shadow depth (3.5) level

[Source: ISO 18451-1:2019, 3.113, modified – The accepted terms “standard shadow depth” and “standard color depth” have been added.

3.7 Covering Power

The ability of the coating to remove color or color difference from the substrate

Note 1: The German expressions “Deckkraft” and “Deckfahigkeit” should be avoided.

Note 2: The term “coverage” is ambiguous, as it is used in some cases to refer to coverage and in others to the rate of spread. More precise terms covering power and propagation rate should always be used.

[Source: ISO 18451-1:2019, 3.47]

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