ColorFlow Training

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Background

You can create a print calibration curve to adjust tonality by simultaneously calibrating cyan, magenta, and yellow inks so that the neutral shades of gray are maintained, while black is calibrated separately for lightness and darkness.

Tasks

Goal
Create a print calibration curve for G7 gray balance using a P2P51 chart. (A simple Tint Ramp chart is not suitable, you must use a measurement chart that contains all G7-specified gray scale patches in order to be able to measure and compute G7 gray balance.)

Task 1: Create a print calibration curve for G7 gray balance

  1. In ColorFlow, click the Print Curves tab.
  2. In the Calibration Curves section at the top left, click the Add button .
    The Devices dialog box appears.
  3. Drag the device "XX Offset Press" that you created in a previous activity to the viewer window and close the Devices dialog box.
  4. Click the Properties icon  in the bottom icon and define the device condition:
    1. From the Plate Setup list, select None. You can also select a plate setup defined in the Plate Curves tab.
    2. From the Screening list, select  20u Staccato  or add the value to the list if it doesn't exist. Skip this step if you selected a plate setup above.
    3. From the Substrate list, choose Type 1 or 2 (coated art) 170 g/m2.
    4. Leave Process Inks as CMYK
    5. Click OK.
  5. Click the Measurement icon . (Note: The Measurement icon will appear as  if you have already created an offset press with the same properties in a previous exercise.)
  6. In the Charts panel, use the Measurable by list control to select your measurement device.
  7. In the Charts list, choose a P2P51 chart suitable for your measuring device.
  8. In a real-life situation, you would Export the P2P51 chart, output the chart from Prinergy and print it on press, and measure the chart in ColorFlow.  For the purpose of this training, you will import a sample P2P51 measurement data file:
    1. Click the Measurements tab at the top of the window.
    2. Click Import.
    3. In the Characterization Print Curve dialog, keep the default Linear (None) value and click OK.
    4. Select the sample P2P51_Sample_Data.cgt file and click Open.
    5. (If you already loaded a measurement file in a previous exercise, you will get a dialog saying "This action will update curves and profiles in color setups using the device condition, discarding adjustments. Continue?" Click Yes.)
    6. Click Close in the bottom right-hand corner of the dialog.
  9. Define the calibration target to G7 aims:
    1. Click the Calibration icon  in the link area between the Calibration Target and the Offset Press panels.
    2. Ensure Show curves in Prinergy check box is selected.
    3. In the Process Inks tab, click the G7 checkbox.
    4. Curves Method: Gray Balance is selected automatically.
    5. Click OK.
      A G7 logo will appear in the Calibration Target panel and a print calibration curve is generated to match the tonality and gray balance specified by G7. 
  10. In the Calibration Curves table list at top left, double-click the name of the curve you just created and enter XX new print calibration curve for G7 (where xx= your initials). Press Return or Enter to set the curve name.

Task 2: Output a page using the G7 print calibration curve in Prinergy

  1. In Prinergy, create a new job and name it as XX print Curve for G7 (where XX = your initials).
  2. Refine GrayBalanceTestFile.pdf with 1stRef-Normz.
  3. Output GrayBalanceTestFile using a Virtual Proof.LoosePage with the G7 print calibration curve you just created:
    1. In the Virtual Proof.LoosePage Process Template dialog box, choose Virtual Proof from the Output To list,
    2. Leave ColorFlow Color Relationship Management unchecked.
    3. Expand the Calibration & Screening panel.
    4. Click the ColorFlow Current State radio button.
    5. Expand the Print Curve drop down list and select XX Print calibration curve for G7 gray balance.
  4. Open the generated output in VPS and measure the 50% patch. 
    Confirm that the gray balance print calibration curve has been applied. 50% cyan should measure 51.1.  50% magenta should measure 54.6. 50% yellow should measure 55.7. 50% black should measure 44.1.

Outcome

You have created and applied a print calibration curve to match output to the G7 gray balance specification.

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