The Tab ‘Exceptions’ in DeviceLink Profiling

Exceptions are used to specifically influence color conversions of special colors. If source and target colors in a color conversion are identical the colors will be linearized. If the color spaces differ, the colors will be optimized and adapted. Exceptions ensure that special properties of colors remain unchanged. The choice of appropriate exceptions thus allows a precise color conversion of specific colors.

The ‘Optimize Technology’ of ColorLogic preserves the properties of the input colors (for example using a single color channel for primary colors or two color channels for secondary colors) and calculates the best possible combination to minimize related color errors.

Only relevant exceptions are available for DeviceLink profiling depending on the combination of color spaces. Options that are not available are grayed out.

If the option Triplex is selected all affected options are automatically activated, too. That way Gray, 100% Black, Duplex, Primaries and Secondaries remain pure. When selecting Duplex all Primaries, Gray and 100% Black remain pure.

Automatic selection of Exceptions

The proper choice of exceptions in DeviceLink profiling can sometimes be an art in itself and ensures hue-accurate, pure and saturated colors as well as print-optimized color behavior, for example when overprinting. In order to facilitate this choice the tab Exceptions contains an option for the automatic selection of the most appropriate exceptions for the selected source and target profiles. Here, different kinds of calculations for color rendering, color distances, device color differences as well as empirical values regarding the preservation of color purity will be combined. To activate this function select the mode Automatic. After a short calculation time the automatically identified exceptions are grayed out. Exceptions that are not implicated are not grayed out and can be activated or deactivated manually. This makes it much easier to choose exceptions appropriately.

Note: We recommend to enable the automatic selection of exceptions for the creation of DeviceLinks by default in order to obtain a good preselection. If you prefer to select exceptions manually or if you would like to adjust the automatically determined settings, select the mode Custom. If you have manually selected exceptions or a DeviceLink preset and then switch to Automatic, previous settings will be overwritten.

Dependency between the Exceptions Gray and White in Soft Proofs

The rendering intent Absolute Colorimetric is often used for soft proofs in order to determine how printed colors will be affected by the color of the paper. It is important to point out that a dependency exists between the Exceptions Gray and White when selecting the setting Proofing and the rendering intent Absolute Colorimetric in CoPrA.

When creating DeviceLink profiles using the rendering intent Absolute Colorimetric the simulation of the paper color will be prevented when the exception Gray is activated. The use of exceptions in combination with the rendering intent Absolute Colorimetric is contradictory and therefore not recommended. For this reason, all exceptions are disabled by default when the setting Proofing is selected in CoPrA. In order to make this dependency even clearer, the exceptions White and Gray are linked to each other. When an exception which is connected to Gray (e.g. Duplex or Triplex) is activated, the exception White will be disabled and grayed out automatically.

Note: Please note that the exception White is only available when Absolute Colorimetric is selected as Rendering intent. The exception White ensures that paper white is not simulated which is especially useful when you would like to achieve an absolute colorimetric simulation for proofs without a simulation of the paper color (e.g. for aesthetic reasons).

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