Apply gradation curve to select objects (8.3)

pdfToolbox 8.3 provides an opportunity to apply filter tone curves to specific objects. This tutorial demonstrates:

  • Set up the appropriate filter.
  • Configure a level for special requirements.
  • Perform levels.
  • And finally check the result.

The purpose of this tutorial is to make a narrow black line with a tone value of 35% a little bit darker. The line that has to be correct uses a particular type of color coding, know as "Separation Black". Other lines in the PDF file are thinner or thicker and has a different tone value.

Attached Files

Launch pdfToolbox Desktop

Open the PDF file "Left_Demo file.pdf"

  1. Go to "File".
  2. Click "Open" to launch the file load dialog box and navigate to the folder where the input PDF file "Left_Demo file" is located.

Open the Inspect panel

  1. Go to "View".
  2. Click "Inspect".

Inspect the PDF file

  1. Select the dashed line.

The dashed line in the middle of the page appears in the print too light. The tone has to be changed from 35% to 55%.

Open the Fixups dialog

  1. Go to "Tools".
  2. Click "Fixups".

Create a new pdfToolbox Fixup

  1. Click on the Fixup action button.
  2. Click "Create New callas pdfToolbox Fixup".

Analyze the Fixup

  1. In the search field search to "Adjust dot gain".
  2. The setting for the tone value has to be changed to a customised setting (later explained).
  3. Here you have to specify a filter that determines which objects have to take place (later explained).
  4. Click on the "plus" button to open a new customised Check.

Create a new customised Check

In the customised Check you have to add some criteria that determines which objects have to take place.

Add Check "Object uses Black"

  1. In the search field search to "Object uses Black".
  2. Click "Add".

Configure Check "Object uses Black"

  1. In the list select "is true".

Add Check "Is Separation color space"

  1. In the search field search to "Is Separation color space".
  2. Click "Add".

Configure Check "Is Separation color space"

  1. In the list select "is true".

Add Check "Is line"

  1. In the search field search to "Is line".
  2. Click "Add".

Configure Check "Is line"

  1. In the list select "is true".

Add Check "Color value 1 for stroke"

  1. In the search field search to "Color value 1 for stroke".
  2. Click "Add".

Configure Check "Color value 1 for stroke"

  1. In the list select "equal to".
  2. Enter the value:
    - Number: 0,35
    - Plus/minus: 0,01

Add Check "Line width"

  1. In the search field search to "Line width".
  2. Click "Add".

Configure Check "Line width"

  1. In the list select "equal to".
  2. Enter the value:
    - Number: 1
    - Plus/minus: 0,01

Rename the customised Check

  1. Enter the name "Separation black line, 35%, 1pt".
  2. Click "OK".

Apply customised Check in Fixup

  1. In the list select "Separation black line, 35%, 1pt".

Open the dot gain curve setting folder

  1. Open the "Dot gain curve setting list".
  2. In the list select "Open folder with configuration files".

Modify existing dot gain curve setting file

Modify existing dot gain curve setting file
  1. Select the dot gain curve setting file "010_25perc.crv".

Modify existing dot gain curve setting file

Modify existing dot gain curve setting file
  1. Make a copy of the dot gain curve setting file "010_25perc.crv".

Modify existing dot gain curve setting file

Modify existing dot gain curve setting file
  1. Change the name to "Change to 55 percent".

Review existing dot gain curve setting data

Open the dot gain curve setting file "010_25perc.crv" in a text editor to review the data. Most text editors are free. For example on Mac you have "TextEdit" and "TextWrangler"; on Windows "Notepad" and "Notepad ++".

Modify existing dot gain curve setting data

Open the dot gain curve setting file "Change to 55 percent.crv" in a text editor to modify.

NOTE: When you edit or change the curve setting file, you have to make absolute sure to maintain the existing gaps between the values as tabs, and not to replace them with single tabs.

  1. If you want to specify a different name, this value must be set from 1 to 0.
  2. The name must be set to an appropriate value that is used. Here "FEATURE_AdjustDotGainMinus25Perc_long" should be "Change to 55 percent".
  3. The desired target values for levels must be registered in the rows affected by tabs. In this case the target value should be 55% (written as 0.55).

Save the curve setting file as "Change to 55 percent.crv".

Apply dot gain curve setting

NOTE: After saving the new dot gain curve setting file, the setting is not in the tone configuration list. You have to close the dialog and open again to see the new setting in the list.

  1. In the list click "Change to 55 percent".

Save the Fixup

  1. Change the name to "Set 35% line to 55%".
  2. Click "OK".

Apply Fixup on PDF file

Apply Fixup on PDF file
  1. Click "Fix".

Save the output PDF file

Save the output PDF file
  1. Save the output PDF file as "Left_Demo file_Processed".
  2. Click "Save".

Review the preflight report

Review the preflight report

The 35% line tone is changed to 55%.

Inspect the processed PDF file "Left_Demo file_Processed"

  1. Select the dashed line.

The tone of the dashed line is changed from 35% to 55%.

Review the processed PDF file "Left_Demo file_Processed.pdf"

At the top is the processed PDF file where the tone of the dashed line is changed to 55%. At the botton the original dashed line with the lighter tone of 35%. In both PDF files the remaining lines are unchanged.

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