Corrects measurement data to a specific set of curves. Data is corrected according to specific conditions (e.g., G7, ISO 20654 SCTV).
Even when every precaution is taken to insure accuracy of the CtP curves and on press, there will always be deviations caused by production and environmental factors. An additional example would be Flexographic printing and defining the exact percentage of the first printed dot or the shape of the highlight bump.
There are three different ways to ensure tone value correction is incorporated properly into measurement data.
Correction according to a tone value curve of an ICC profile:
Specify a profile and the measured values are adjusted to achieve the same tone value increase curves as those of the selected profile.
Note: Depending on the loaded measurement data only ICC profiles fitting the color space are shown (e.g. CMYK or multicolor. In this example a 7 inks multicolor profile is selected).
Correction according to:
Tone value curves are calculated to match the requirements of G7 Gray Balance, ISO 20654 (SCTV), G7 + ISO 20654 (SCTV) or ISO 20654 (MultiColor).
Note: G7 is defined to work with CMYK only. However it is possible to apply the G7 process on the CMYK parts of a multicolor measurement file. The additional (multicolor) channels will not be effected. The G7 calibration process ensures that the CMY curves reach a neutral gray of defined lightness values throughout the entire gray balance curve.
G7 + ISO 20654: G7 is defined to work with CMYK only. However it is possible to apply the G7 process on the CMYK parts of a multicolor measurement file and the additional (multicolor) channels will be corrected according to ISO 20654.
ISO 20654 (Multicolor): Adjusts the Multicolor channels according to ISO 20654 and leaves the CMYK channels untouched. This is useful when the CMYK parts have been calibrated according to other standards, like PSO density curves or G7 and only the additional Multicolor channels need to match ISO 20654 (SCTV) requirements.
Correction according to TVI targets:
Manual editing of each channel allows predefining the increases in tone value to be incorporated in the measurement data.
This feature works for CMYK and multicolor color spaces. Depending on the data that was loaded into ColorAnt, additional or fewer channels are displayed as can be seen in the screenshot showing a CMYK file on the left and a 7 ink file on the right.
Protect Lights (%): Leaves the highlights untouched when applying any of the three correction modes.
Specify the percentage up to which the highlights are to be protected. Review the measurement data to ensure a clean transition between the protected and unprotected area. This feature is especially helpful for Flexo printing as it avoids over compensation of dot gain in the highlights.
Save Curves as Photoshop ACV format and Save Curves as ISO18620 XML format: Correction curves can be exported as Photoshop gradation curves (ACV) and as XML according to ISO 18620. The curves are automatically saved in the folder /Users/USERNAME/Documents/ColorAnt/Linearity on macOS systems or C:/Users/USERNAME/Documents/ColorAnt/Linearity on Windows PCs. These curves can then be used in either Adobe Photoshop or any external RIP software that supports the ISO 18620 standard.
Custom Tone Value – Corrections
ColorAnt’s Custom Tone Value feature is specifically designed for manual corrections such as smoothing, adding or deleting points or changing individual TVI values. In addition, save custom curves and apply them on other channels and data.
- Click on the Smooth button to smooth the curve. Only a few fulcrums are displayed after smoothing; ColorAnt is not deleting any original fulcrums but helps to better optimize the data by reducing the amount of values. Apply the corrections on the measurement data and all fulcrums will be adjusted to fit the smoothed curve.
- In order to add any number of additional ink values, click on the Add button. Navigate to the new empty entry that will appear in the table and type in the desired Ink Value and the Increase value in dot percentage required. Apply the changes by hitting the tabulator or enter key on the keyboard. The curve will be immediately updated.
Note: The original curve will be displayed in gray for as a reference.
- Change any of the existing Increase values in the table by simply selecting an entry and changing the numbers.
- To delete an Ink Value, select the desired entry in the table and click Delete.
- Save the curve for later use. Click on Save as and enter a name for the curve in the appearing dialog.
- To apply the manual editing, click on OK and return to the Tone Value dialog. The edited curve will be marked as Customize.