Ink settings are required for separation and DotProof profiles. They include screening, usage, and overprint parameters. For DotProof profiles, they also include RIP compensation curves.
You can define ink settings on both the characterization and project level via Tools & Actions > Tools > Ink Settings.
- Characterization: Edit the ink settings of all inks defined in the characterization (process and spot colors). Changes here apply to all projects based on this characterization.
- Project > Proof tab: Edit the ink settings of all colors used in the project. Changes here affect only the current project but not the underlying characterization.
- Project > Separation tab: Edit only the actual output colors as defined by the target color space.
Screening
Screening defines the screening type (AM/FM), angles, and ruling for each ink channel to reproduce the target press conditions.
Different grids (screening configurations) help avoid moiré patterns. If your printer uses more than four inks, complementary colors (Red–Cyan, Green–Magenta) can share the same grid, unless they differ strongly in lightness.
Screen angles should differ by at least 15°. You can set the angles manually or choose one of the available presets.
Ruling defines the screen frequency, i.e. the number of lines or dots per inch (lpi). Higher rulings produce finer, more detailed screens, while lower rulings are coarser and more stable. Use a ruling that matches the target printing process.
Important: For DotProof profiles, the screening settings should match the actual printing conditions, including the Imagesetter Resolution used to create the 1-bit files.
Usage
The usage setting defines the role of each ink in the separation or DotProof profile.
It also affects the number and selection of test chart patches used for DotProof iterations.
| Option | Description |
|---|---|
| Separation Cyan/Magenta/Yellow/other | For process inks and other colors that must be reproduced precisely. Inks that are defined as separations are profiled with all overprint information from the characterization. For separation profiles, all output inks — except Contrast (Black) — require this setting. |
| Contrast Black/other | For dark or contrast-enhancing inks such as black. |
| Spot Color | For colors used only as spot inks that are not part of the image separation. |
| Solid Only | For colors that are used only as solid tones. |
| Color Database | Used automatically when an entire spot color library is added as an "ink" to a project (e.g., CMYK + spot color library). Enables dynamic profile generation. |
Overprint
By default, overprinting is enabled for all colors. This is indicated in the matrix by the All overprints, no restrictions icon. Each cell in the matrix represents how one color overprints another.
To adjust change how one color overprints another, click the corresponding icon in the matrix to toggle through the available options.
| Option | Description |
|---|---|
|
|
Allows unrestricted overprinting for smooth gradients and maximum gamut. Inks are only mixed where it makes sense colorimetrically. |
| Completely prevents colors from overprinting. Useful to avoid color shifts caused by register deviations in conventional printing, especially in Flexo. However, complete knockouts may result in steep tone value curves and visible transitions between non-overprinting colors. |
|
| Prevents raster-to-raster overprints but allows tiny overlaps (a few percent) for smooth transitions. These intentional overlaps usually do not cause visible color shifts in case of register deviations. Recommended for digital presses with precise registration, but can also be used in offset printing. |
When calculating separation rules, OpenColor takes the project’s TAC (Total Area Coverage) and overprint settings into account to prevent over-inking and moiré during print production.
Avoid moiré in AM screening
In case of AM screening, it may be useful to allow colors with the same screening configuration to overprint with solids only. In the following example, Cyan and Red are both set to Configuration 1. If the overprint behavior is set to Suppress Raster-Raster overprints, Cyan will only print with solid Red and vice versa.
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