EasyMedia - Linearization

This article covers Linearization, the calibration step in the EasyMedia Wizard that follows Transitions when light inks are used. This process determines the maximum usable ink value for each channel and builds correction curves to produce a linear output.

Choose how to get started

Create a new linearization curve

Run Wizard (Print, Measure, and Build a target)

If you choose to print and measure a target, follow these steps:

Load or import an existing measurement file

As the name suggests, "Load an existing measurement file" allows you to load a measurement file from different sources:

• Load the last measurement file
• Load a file in the project's directory
• Load another file
• Import from the current linearization file (.ppi files)

Create from scratch

If you choose to create a new linearization curve from scratch, the module takes you directly to the linearization curve editor, where you can review the linearization values either as a graph or as numeric values and adjust them manually without printing or measuring a target first.

Relinearize

If you want to update an existing calibration while keeping its current settings, use the Relinearize option.

For more information, see the dedicated article.

G7® Linearization

The G7® Linearization option is used when you want to align the printer behavior with G7 calibration principles during the linearization step.

This option focuses on tone reproduction and gray balance behavior at the linearization stage. It is intended for workflows where G7 compliance or G7-like behavior is required from the beginning of the calibration process.

Edit or check the current linearization

The "Edit or check current linearization" option is available only if the project already includes a linearization setup. 

In this case, the options below (Run wizard, Load a measurement file, or Create from scratch) are not available, since you can only review or edit the curve values of the existing linearization.

Verify the Linearization Curve

Once the measurements are complete, the interface displays a two-dimensional graph showing the measured values against the ink percentage. You can choose to display the graph using either spectral density or Hue (ab):

Spectral Density Hue (ab)

• Vertical Axis (Y): Represents spectral density, expressed as a percentage. 
• Horizontal Axis (X): Represents ink percentage, expressed as a percentage.

• In this view, the spider graph displays the hue of primary colors such as CMY, as well as additional colors such as Orange, Green, or Violet (if applicable).

• Lab / Lch values: When moving the mouse over the curve, the corresponding measured values for the selected point are displayed on the left side of the interface. These values can be shown in either Lab or Lch format.
• Ink channel buttons: On the right side of the interface, one button is available for each ink channel. Clicking one of these buttons filters the display so that only the selected color is shown. The "All" button restores the full display and shows all color curves again.
• Pmax / Dmax: These fields allow you to adjust the target values for each ink channel. One field is available for each color, with values ranging from 0.0 to 100.0:
  • Pmax: Indicates the maximum ink percentage on the horizontal axis.
  • Dmax: Indicates the maximum spectral density on the vertical axis.
• Auto button: Restores the automatically calculated Pmax and Dmax values and cancels any manual changes made to these fields.

• Target...: Opens the Target Setup window, where you can define the target behavior used to build the linearization curve. You can choose one of the following options:

    Info

  Only one option can be selected at a time. These options are useful when you want to control how the linearization curve is built, depending on whether you want a neutral default behavior, a density-based target, or a reference based on an existing calibration condition.

  • Do not use any target (flat curve): Builds the curve without applying a specific target correction.
  • Use Dmax/DotGain curves as Target (Not available yet): Uses density and dot gain target curves as the reference.
  • Use a reference file as the Target: Uses an external reference file as the target.
• Number of control points: Each point on the graph represents a measured value from the printed target and is used to build the curve. For example, a standard target with 21 patches produces 21 data points. The "Number of control points" drop-down determines how the curve's control points are managed: Dynamic lets EasyMedia automatically choose the number of control points, while Fixed reveals an additional field where you can manually set the number (5 to 101).

• Auto-Smoothing: Improves the linearization curve by reducing the impact of color measurement inaccuracies. This option is especially useful when working with printers that show high variability, with difficult media such as textiles or corrugated materials, or when spectrophotometer measurements are less consistent.

    Warning

  When enabled, the Number of control points setting is disabled because the software automatically manages the curve.

Tips and Tricks

• You might be interested in consulting: Technical knowledge > Technical glossary > Color Management.
• The maximum ink value for each channel is defined when the measured density reaches 99% of its maximum value. This value is called Pmax and is used as the Ink Restriction for that color:
  
• In most cases, the default values provide satisfactory results. However, adjusting them carefully can improve calibration stability, reduce ink consumption, and help create a more optimized ICC profile.
• Evaluating Spectral Density, and the color values shown in Lch (especially chroma and hue), can help determine the most appropriate Pmax, and therefore establish the Ink Restriction.
• For Black (K), use the L* value in Lab to identify the optimal Pmax, which is generally the lowest L* value. You should also visually inspect the printed linearization chart to confirm that the selected Pmax matches the printed result.

Linearization Statistics

Clicking "Next" displays the Linearization Statistics screen:

This screen shows the measured differences for each ink channel and indicates whether relinearization may be useful. The displayed statistics may include:

• Density shift: difference in density compared to the reference condition
• Average DeltaE: average color difference
• Max DeltaE: highest color difference measured
• Average Curve Correction: average correction that would be applied to the curve
• Curve Correction: Maximum correction that would be applied

The screen also shows the reference device and current device values, including the measured white point.

Edit Linearization Curve

Clicking the "Next" button displays the linearization curve editor. At this stage, you can review and adjust the linearization curves manually:

• Control points: You can choose how many control points are displayed and can be edited in the curve. The available options are: 5, 10, 20, 100, and Free. Using more control points allows for finer adjustments, while fewer points make the curve easier to edit.
• Save G7 correction curves: The "Save G7 Correction Curves" button opens the file explorer and allows you to save the current correction curves as a file. This can be useful if you want to keep a copy of the generated curves for later reuse, comparison, or reference in a G7-related workflow.

Use Case

In this example, Chroma is used to select the optimal Ink Restriction or Pmax.

Select Lch in EasyMedia, then observe the measured c values on the left side of the interface as you move the mouse over the measurement data.

EasyMedia automatically determines a Pmax value based on a calculated Dmax at 99%. In this example, the pre-determined value gives a Chroma of 66.8 at a Pmax of 85.8%. However, the peak Chroma is 66.9 at a Pmax of 69.4%.

This means that reducing the Ink Restriction lowers ink consumption without reducing color saturation.

Also, check the Spectral Density values, shown as the small d under Measure on the left side of EasyMedia, to make sure there is no significant loss of density when adjusting the Ink Restriction.

Using the same example, you can also observe the effect of the Ink Restriction on the Hue angle for Cyan.

Beyond 69.4% Pmax, the hue shifts from cyan toward blue, and the measured data points become very close to one another. This indicates that increasing ink further does not improve the result and may instead alter the color behavior.

Restricting inks based on Hue, in addition to Chroma, can help produce a more accurate ICC profile. In the case of Cyan, excessive ink can cause a blue hue at 100% Cyan. When ICC charts are printed and measured with this behavior, color mapping becomes less accurate because the software interprets Cyan as being bluer than expected.

Correction curves

The correction curves are used to produce a linear output for each color. They modify the printer behavior so that the measured result matches the expected progression.

In the illustration below, the measured results of the linearization target (A) are mapped to the corresponding correction curve (B) in order to achieve the linear behavior of the device (C).

At this stage, the selected Pmax becomes the maximum usable value, or 100% Ink Restriction, for the corresponding color channel.

Next Step

Once you have finished checking and/or modifying the linearization values, click "Next".

The module will ask if you want to test the settings you just adjusted. If you choose to do so, the printing/measurement settings will appear again.

After printing, the wizard will ask if the test results were satisfactory. If so, you can proceed to Ink Limit.