ColorAnt | Smoothing

Smoothing

Automatically Smooth Measurement Data

Smoothing Measurement Data

Common measurement data issues:

  • Inconsistent or illogical gradation values for lighter or darker tones compared to adjacent colors.
  • Irregular data caused by variations in the printing process or contamination of color patches during measurement (e.g., mechanical interference from the device).
  • Incorrect color readings, such as a green patch being recorded instead of a red value.

Smoothing and/or Correcting Measurement Data

The Smoothing tool corrects inhomogeneous measurement data and bumpy curves. It uses an interpolation method that fits perfectly to already smoothed data. The amount of smoothing is set with a slider, fitting the entire measurement data into the mathematical model. Thereby, the general characteristic of the measurement data is maintained.

Important: It is strongly recommended to check the Correct Measurement Data checkbox before applying the Smoothing tool. Without correction, the smoothing process may transfer errors from the data to adjacent colors and may not achieve optimal results.

Correct Measurement Data: Detects faulty or “illogical” measured values and replaces data with proper measurement values. If the data is left uncorrected, inaccurate ICC profiles are often the result.

Note: If you only want to correct the measurement data without smoothing, set the Smoothing Factor to zero, see screenshot.

Smoothing Factor: Specifies the strength of the smoothing.
Note: When using the Automatic tool, the Smoothing factor is set to 50%.

Protect Highlights and Shadows: This feature preserves highlight and shadow areas by handling them separately and maintaining their characteristics during the smoothing process. This is useful for maintaining the unique characteristics of high dot gain often seen in flexographic printing.
Flexographic printing processes frequently produce a bump curve in the highlight area. By enabling Protect Highlights and Shadows, these curves can be retained, ensuring accurate reproduction of the intended print behavior.

Note: When deciding whether to use the Protect Highlights and Shadows option, consider the type of printing system as well as the intended use of the characterization data and the profile created from it.
A very high dot gain or the loss of highlights may not be a mere temporary defect but a known characteristic of the printing process that will later be corrected on the plate (e.g., with special highlight “bump” curves in flexographic printing). In such a case, the highlights should be smoothed completely without protecting the highlights in anticipation of that later correction in the RIP. However, if no additional compensation correction is applied in the RIP, the characteristics of the highlights and shadows should be protected while applying smoothing.

Example of Smoothing with and without the Protect Highlights and Shadows option

TVI view of the original data before smoothing: High and uneven dot gain in the highlights, bumpy curves in the midtones, and a K curve that differs from CMY in the shadow areas.

After smoothing without protecting the highlights and shadows: The curves are perfectly smoothed even in the highlights and shadows. However, the special characteristics of the highlights and shadows have been lost.

After smoothing with protection of highlights and shadows: The unevenness in the highlights has been removed and the curves are smooth overall, but the characteristics of the highlights and the ratio of the K curve to the CMY curves in the shadows have been preserved.

 

ColorAnt | White – Black Correction

White/Black Correction

Apply Manual Corrections to Paper White

Correcting the White and Black Point

Overview

This tool allows adjusting the paper white using the White Correction and the darkest color using the Black Correction.

The White Correction tool allows manual correction of the whitest patch of the measurement data, which is usually the paper or substrate color. The tool is applied to a single measurement file. A correction by changing the Lab or LCh input value is useful in cases where either a specific target white point is to be achieved or corrections are required to lighten, darken or recolor the data. The manual correction is then applied to the entire measurement data, leaving the print characteristics intact.

White Correction: This calculates the effect of the changed paper white on the measurement values of a test chart. In ColorAnt, three different methods are available for calculating this effect: ColorLogic Default, ISO 13655 and Relative colorimetric.

Direct Measurement of the White Point

Changes in paper white affect the entire color space. Major changes in paper white also have a strong effect on the primary colors.

The white point can be (re-)measured directly from within the White/Black Correction tool. This measurement data can then be used to correct the white point of the selected dataset.

Follow these steps to adjust the white point:

  1. Load the measurement data to be corrected and open the White/Black Correction tool.
  2. Click on the eyedropper icon and select the option Measure.
  3. The Measure Tool opens with the preselected chart for measuring the paper white with a single patch.
  4. After the measurement, the new white point data is transmitted back to the White/Black Correction tool and is applied to the entire measurement data keeping the print characteristic intact.
    Note: The white point measurement is also listed under Data Sets.

White Correction Methods

ColorLogic Default: This method uses a spectral color model to apply corrections that produce the most realistic results possible. This works best when both the data to be changed and the white taken from another file are spectral data. If spectral data is not available, ColorLogic Default works in the same way as ISO 13655, assuming that shadows are not affected and that the impact on primary colors is much smaller.

ISO 13655: In the highlight areas and colorful primary colors, this method is similar to the Relative colorimetric method. However, this method assumes that the shadows and very dark colors are not changed. It corresponds to the Substrate Corrected Color Aim (SCCA) method.

Relative colorimetric: Changing the paper white will modify the entire color space. Major changes to the paper white also have a strong effect on the primary colors.

Procedure for White Correction:

  1. Load the measurement data to be corrected and the data containing measurements of the new paper white.
  2. Click on White/Black Correction
  3. Select the mode for adjusting the corrections: LCh or Lab Color Mode. The mode can be changed at any time. With LCh the hue or chroma can be adjusted independently, while the corrections in a* and b* change hue and chroma simultaneously. The split color patch displays the original white on the left side and the modified white on the right side.
  4. The white point can be edited either manually with the sliders or by entering Lab values. Alternatively, a new white point can be selected from another data file using the eyedropper icon. Simply click on it and select the data file that contains the desired white point. The new white point will be selected automatically.
    Notes: The eyedropper will pick the whites patch of the selected file. If spectral data is detected, the tool will use it according to the selected Method.
    The sliders allow for small changes. More precise numbers can be entered in the dialog box. The sliders are reset afterwards.
  5. If the lightness (L* value) is changed while using the Relative colorimetric method, the darkest colors of the measurement files are usually affected as well. If the black point and the darkest colors are not to be changed, the ISO 13655 method should be used. Both methods, Relative colorimetric and ISO 13655, apply calculations with colorimetric data. Only the ColorLogic Default method uses the full spectral data and a spectral model for the calculation.
    Note: Depending on the color difference of the paper white and the presence of optical brighteners, this may affect the primary colors.
  6. Clicking the Reset button will discard any slider modifications.
  7. Clicking the Start button applies all changes to the entire measurement file. The dialog is closed automatically after the calculation.

Black Correction

Black Correction: This method can be used to change the darkest black, thereby scaling the entire dataset to the modified black point. This is beneficial when black has been measured too dark or too light compared to the visual appearance. Common scenarios include materials used in industrial applications such as ceramics, textiles, glass, etc.
Important: Black Correction is not available when using the Relative Colorimetric Method.

Procedure for Black Correction:

  1. Load measurement data.
  2. Click on White/Black Correction.
  3. Select either ColorLogic Default or ISO 13655.
    Note: Relative colorimetric does not allow changes to the black point.
  4. Adjust the correction in LCh or Lab Color Mode. LCh allows adjustment of the hue or chroma independently whereas corrections in a* and b* will change hue and chroma simultaneously. The split color patch displays the original black on the left side and the modified black on the right side.
  5. The black point can be edited either manually with the sliders or by entering Lab values.
  6. Click the Reset button to discard any slider modifications.
  7. Click Start to apply the corrections. The dialog is closed automatically after the calculation.

ColorAnt | Correction

Correction

Correct and detect faulty measurement

Correction

Detects faulty or “illogical” measured values and replaces data with proper measurement values. If the data is left uncorrected, inaccurate ICC profiles are often the result.

Important: For optimum results, Correction must be applied before the Smoothing.

Common measurement data issues:

  • Illogical measured data of lighter or darker gradation values based on adjacent colors.
  • Illogical data due to variations in the printing process or contaminated color patches (from the mechanics of the device) when measuring.
  • Instead of a red color value, there is a green patch.

Actions

  1. Correct bad measurements fixes the above mentioned common issues. This option should always be active when using the tool.
  2. Protects Lights allows selection to which percentage value the correction shall be performed. Values below this value are protected. The slider values range from 0% to 50%.
    Features for flexographic printing: The flexographic print processes often exhibits a bump curve in the highlighted area. These types of curves can be retained by using Protect Lights. In some flexo data cases it may not be necessary.
  3. Optimize overprints improves patches with overprinting darker colors such as tertiary colors. A subtractive color model is used for the optimization. In other words, the model assumes that adding colors leads to a darker color appearance. Some printing processes like electrophotographic and inkjet printers do not necessarily behave like this. In such cases, it is not recommended to use this option. We would recommend disabling this option unless you desire data that perfectly behaves subtractive.

Note: The Auto tool uses only the Correct bad measurements option.

ColorAnt | Redundancies

Redundancies

Correct Redundancies in measurement data

Redundancies

Redundant color patches can cause errors when creating profiles, especially if they have very different measurement values.
The Redundancies tool corrects the measured values of multiple color patches by averaging the redundant values. Corrected redundant color patches then have identical values.

The methods for correcting redundant color patches are the same as in the Averaging tool.

Auto: Different methods are used depending on the number of color patches. It is therefore quite possible that some color patches are processed with a different method than others. If there are two identical color patches with differing measurement values and one of the measurement values is recognized as an outlier, this method automatically selects the plausible color value.
For more than three color patches, the Weighted or Median methods are used. If there are a large number of measured values, both the Median and the Weighted methods consider values that are far apart to a lesser extent for averaging.
Note: Color patches within a gradient are automatically sorted according to their measurement values. This correction of "wrong" primary gradients is intentional since wrong primaries can lead to various other problems.

As the most intelligent method, Auto is preferable to the other methods.

Arithmetic: For the arithmetic averaging of values of several color patches, i.e. the average of the measurements (if, for example, only two color patches are to be averaged).

Median: Is a statistical method and denotes a boundary between two halves. The median is the "middle value" of a sorted list of numbers. Half of the numbers in the list are smaller and the other half of the numbers are larger than the median.

Weighted: Calculates a weighted mean value, i.e. a mean value to which some values contribute more than others. Outliers can be considered to a lesser extent for averaging.

Remove duplicate patches: Removes multiple color patches. First the average color value is calculated, then all but one identical color values are removed.

Note: The Redundancies tool can be used to average emissive data, such as multiple spectral measurements of a light source stored in a measurement file without DCS data. If the measurements are spectral, the averaging is performed on the spectral data.