Colorimetry

Delta E

Select the delta E formula to be used for calculating the average deviation between the CxF/X-4 spot color definition selected in the library file and the measurement made for the printed sample. Default is dE2000.

Also enter a tolerance value for this color deviation. A pass/fail icon will indicate if the CxF/X-4 color is similar enough or out of tolerance.

Illuminant

Standard light source expected to be used for viewing samples of the printed color.

This option affects the way the measurement data is converted to CIE Lab. Different illuminants will produce different delta E values in the printer validation process.

Standard observer

Standardized angle of the average human eye at which samples of the printed color are expected to be viewed. This angle determines the field of view and thus the way a person perceives color.

This option affects the way the measurement data is converted to CIE Lab. Different observation angles will produce different delta E values in the printer validation process.

Metamerism

Metamerism index

Enter a tolerance value for the metamerism index (MI) calculated for the difference between the CxF/X-4 spot color definition selected in the library file and the measurement made for the printed sample.

The tolerance limit is the maximum deviation permitted from a target value of 0 dE. A value of 0 means that the reference and measured sample must show exactly the same color deviations under both illuminants. A value of 3.0 means that the samples are not allowed to differ in metamerism by more than 3.0 delta E.

ORIS CxF Toolbox calculates up to six metamerism index values for every measurement, depending on the number of selected reference and test illuminants. Validation is successful if all of these MI values are within the tolerance limit. Otherwise validation fails .

Reference/Test illuminants

Select the lighting conditions to be used for calculating the metamerism index (MI) values. You can use one or two reference illuminants and up to three test illuminants.

The MI is a delta E value calculated from the difference between the following:

• CIE Lab deviation between reference and measured sample viewed under a reference illuminant (e.g. D50)

• CIE Lab deviation between reference and measured sample viewed under a test illuminant (e.g. A, C or F11)

Note:

You can disable the validation of the metamerism index by selecting the setting --- for either all reference illuminants or all test illuminants. In this case there will only be a colorimetric validation (delta E).

CxF/X-4 Reference Columns

Use these options to select the color information to be displayed in the list of CxF/X-4 References. You can hide and display various types of data.

List of CxF/X-4 References (Spot Color Library)

dE values

The deviation between the CxF/X-4 spot color in the library file and the measurement can be calculated according to various dE formulas. Select the formulas to be shown in the list:

dE – dE94 – dE2000 – dE CMC

Note:

The dE formulas selected here have no effect on how ORIS CxF Toolbox determines the best matching CxF/X-4 color. This calculation is always done using the formula selected under Colorimetry (dE2000 by default).

Lab values

Lightness (L*) and hue (a*, b*) values for CxF/X-4 color

Chroma and hue values

Chromaticity (C*) and hue angle (h°) for CxF/X-4 color

Lab difference values

Difference in lightness (dL*) and hue (da*, db*) between CxF/X-4 color and measurement

Chroma and hue difference values

Difference in chromaticity (dC*) and hue angle (dh°) between CxF/X-4 color and measurement

Metamerism info

Metamerism index values calculated for the selected reference illuminants and test illuminants.