Why use Advanced Ink Restrictions?

The Advanced Ink Restrictions option allows the user to add some refinement to the settings for Dark Ink restrictions, as well as a greater degree of control for setting Light Ink restrictions, or in the case of printers with multi-level dot size and/or multiple strike capabilities.

If your printer is a solvent printer with light inks, and you see issues with the light inks when you print Ink Restriction Verification Swatch.pdf file, you may want to set the "Light" Ink Restrictions lower than the 20% difference that is set when using the Basic Ink Restrictions option. For solvent printers we recommend 50-70%. Reprint the swatch to verify.

Advanced Ink Restrictions is the only place that Light Ink can be addressed. During this step you have a chance to restricted and limit the amount of light ink used in the print. The Ink Limits step later in the profiling process is only concerned with 3-4 color combinations of dark inks at the maximum level for the affected pixels.

How To Print Test Swatches:

Default Test Print option on the Advanced Tab:

• Use the default swatch and click > Print Swatch.  This will create 2 jobs that are sent to print.  The first is a swatch that uses ONLY the Light inks.  The second is a job that uses the dark inks with a blend of the light inks. 

Custom Test Print options on the Advanced Tab - disabling the "default" check box and using the drop-down menu to select one of the following:

• Choose the " darkinkrestriction" file, as seen below:
  
• Or Choose the "Ink Restriction Swatch" file (use the CMYKRGB if you have this ink configuration).

These test swatches use a different layout patterns have the swatches in a different layout, this is a matter of preference. On some Grand Format and Superwide printers it might be desirable to enlarge this image to a more "Real World" size. Also printing multiple copies across the width of the printer helps to see the average print quality and determine if there are any heater issues with solvent.

You will want to evaluate the test prints for the following:

• Eliminate "Waste Ink" . With UV printers this also means preforming an "Abrasion Test" to make sure the ink does not come off easily.
• Look for cockling, bleeding, puddling, and other print quality issues to eliminate artifacts.

Setting Dark Ink Restrictions:

• Set all of the "Light" ink levels (designated by the lower case letters) to 0% and the "Dark" ink levels (designated by the upper case letters) to 100% and click > Print Swatch.
• If you are using the "darkinkrestriction" file, review the CMY row and look for the maximum swatch that displays no artifacts. Double-check your secondary (RGB) colors on either side of the desired percentage. This percentage is a starting point for setting your dark ink values.
• If you are using the "Ink Restriction Swatch" file, review each of the primary color channels and look for the maximum swatch that displays no artifacts. To dial in the exact percentage, use a hand-held color sampling device and click > Measurement Tool to get objective data.

Measurement Tool - Measure Color Dialog

Choose the desired measurement type:

• LAB
• LCH
• Densitometric (Density Values). Also see Target Density.

Records a series of measurements, when you switch between types you will start with a new index.

Follow the on-screen instructions for calibrating the device and measuring the patches.

Review the values in the column for the channel you are currently working on.

Watch as the values increase and decrease, it will display Deltas against previous measurements.

You can click > Clear to start a new index. 

You can click > Export to save readings as .den or .txt file.

Enable > Plot Measurements to see a chart of your readings based on your measurement type.

There are two different methods for determine the optimal percentage of ink. Both methods are valid and lend to achieving different output objectives.

1) Density - Find the point where additional ink does not increase in optical density.

You can use the Target Density chart or plot the measured points to find a "plateau" in the readings.

Look for flat lines because "plateaus" indicate excessive ink.

Generally, Target Density is used when you are proofing or trying to simulate a different printing method on a digital printer.

2) Chroma - Find the point where additional ink does not increase in chroma or hue.

Look for a Chroma Hook when you plot the measured points to find the percentage just before the curve.

A Chroma "Hook" mean no gain in hue for that channel so the Gamut does not benefit from more ink.

Generally, the Chroma method is used to achieve maximum gamut on a digital printer.

Setting Light Ink Restrictions:

Once you have determined you "Dark" ink levels, enter a percentage for your "Light" ink levels.

• Most water-based printers - set the light ink levels to 80% of the dark ink level.
• UV printers - set the light ink levels to 80% of the dark ink level.
• Solvent printers - set the light ink levels to 50-70% of the dark ink level.

Reprint to verify:

Use the drop-down list to select the "Ink Restriction Verification Swatch" and click > Print Swatch. This will create a new test file using the values seen in the software.

• We will need to evaluate this combination to make sure that the use of so much light ink doesn't cause problems. 
• Observe the transition from light to dark.  Is there a smooth transition?  If an abrupt change is noted, you will need to consider lowering the light ink restriction.
• Examine the swatches on the left side of the print.  This area shows combinations of ink in which the demand is for 100% of one color and then increasing amounts of a light ink.
• As the light ink increases, look for problems in the 2 color combination that become visible as the demand increases.  An example would be the row that has 100% Magenta in every patch.  As the demand for Cyan ink increases, the first swatches are printed with more and more Light Cyan.  At 50% demand for Cyan, you will see the maximum use of Light Cyan.  As the demand for goes above 50% the Light Ink decreases as the Dark Cyan increases.  If there are problems with too much carrier or solvent with the Light Ink it will show as bleeding or puddling problems as the use of Light Ink increases.  This will be seen at the "130 to 150" range. 
• Based on where the bleeding or puddling occurs you will be able to determine how much to lower the Light Ink restriction.  Again, for example, if the puddling is seen at 150 but not at 140, that means that the Light Ink is too much when set to match the Dark Ink setting.  Lower the Light Ink setting to 80% of the Dark Ink setting.  (40% =80% of 50.).
• Go back to the software dialog to re-set the ink restriction values to reflect the appropriate changes. 
• Reprint to verify as many times as needed.

Note: Some user prefer to set light inks lower (around 30-40%) and go up if needed instead of using the "Ink Restriction Verification Swatch" to verify you haven't used too much. This may require more test prints to verify you are getting the most out of your light inks as possible, but in some cases it give sharper results for first-time users.

Unless you have seen a need in previous profiling for your ink and media to adjust the Transition Controls, make sure the settings for this option are at (0).  Click here for more information on when to use Transition Controls.

Once you have set the ink restrictions and there are no puddling or bleeding issues exhibited, go on to the Calibration - Linearization step.

Back to Ink Restrictions.

MeasureTool.jpg (image/jpeg)
Density.jpg (image/jpeg)
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AdvancedIR.jpg (image/jpeg)
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