Background
Most of ColorFlow's color control elements control the color reproduction of process inks
on printing devices. Process inks, typically CMYK, are translucent inks
that are overprinted in various combinations on the output device to achieve
the a desired color appearance.
Spot inks are specially Specially mixed
inks that are printed by output devices in addition to spot inks with a set color appearance can be printed in addition to process inks. You can control the tonality of spot inks separately from process inks.
In ColorFlow,
a default spot ink (black) by default, the process color (Black) calibration curve is used for an undefined spot ink
. You can add more spot inks in addition to the default one for a curve-controlled device condition or a print transfer curve. You can add a spot ink that uses the same calibration curve as a process ink. You can also add a custom spot ink that uses a unique curve, but you can also choose to use C, M or Y as the default calibration curve for undefined spots.
If you wish to apply a unique curve to control the tonality of a spot, you create a new spot ink channel and define a unique curve for the spot channel.
to control its tonality. Tasks
Goal
Create and add a an additional custom spot ink for the channel to a CMYK print calibration curve you created in in a previous activity.
Task 1: Add a spot ink to
the a print calibration curve
- In ColorFlow, click the Print Curves tab.
- In the Print Calibration Curves list table, find and click the print calibration curve XX new print calibration curve for tonal match.
- In the curve object in the Viewer window, click the Property icon
Image Removed
Image Added. - In the Device Condition Properties dialog box, in the Spot Inks section, click the Add button
Image Removed
Image Added. - A spot ink item is added to the Spot Inks list with the default name Spot 1.
- Define the spot ink:
- Double-click the Spot 1 column and enter
Pantone 123
as the name of your spot ink.
- Double-click the Color column and then , click the RGB tab.Enter 255 for Red, 199 for Green, and 44 for BlueSwatches tab and choose any color you like for the spot appearance.
- Click OK.
- Click the Curve on the default Black curve in the Curve column and choose Custom from the drop-down list.
- Click OK.
- Create a Tint Ramp chart:
- Click the Measurement icon
Image Removed.
Image Added in the Offset Press panel. (Note: The Measurement icon will appear as
Image Added if you have already created an offset press Device Condition with the same properties in a previous exercise.) - In the Charts section, click the Add button
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Image Added. - A chart appears in the Charts list with a default name.
- From the Chart Type list, choose Tint Ramp.
- In the Tint Set section, click the Edit button
Image Removed
Image Added. - Click the Add button
Image Removed
Image Addedand enter 0 the values 10 25 50 75 90 100
. - Click OK.
- if a Tint Set with those values doesn't already exist.
- Click OK.
- From the Process Ink Set list, choose None (spot inks only).
- Click Save.
- Enter Manually enter the measurement values. In In a real-life situation, you might need to print the chart and measure the chart using would print a tint ramp chart with the designated spot ink and measure it with a measurement device. For the purpose of this training, you will enter the EDA values.
Note: If the spot ink was manually SCTV (Spot Color Tone Values). Spot Color Tone Value is a newer ISO method for controlling the tonal values of spot inks, and requires a spectrophotometer that has the SCTV method implemented.
Note: If the spot ink is added when you first define the curve properties, you can measure the CMYK and any spot colors directly in the Chart tab. If the Charts tab by clicking on Measure...
But if you add additional spot inks after you have done the measurementthe original chart measurements, you must enter or measure the spot ink values by clicking on the View button in the Measurement Measurements tab.
Enter Measurement values:
- Click the Measurement Measurements tab.
- Click View to open the Tonal Response Tint Ramp Measurement dialog box.
- Click Spot.
- From the Spot Ink list, choose Pantone 123.
- The
Pantone 123
spot ink created in the previous step is automatically selected in the Spot Ink list at top left. - In the Tint In Values section at the bottom left, select the
10 25 50 75 90
Tint Set created in the previous step. In the Tonal In the Tonal Response section, enter the following EDA values: SCTV values: (The SCTV metric is selected by default, but you can switch to Murray-Davies EDA if your spectrophotometer doesn't support SCTV.)
| | | |
---|
0 | 0 |
10 | 12 |
25 | 29 |
50 | 57 |
75 | 84 |
90 | 96 |
100 | 100 |
Click OK.
Task 2: Define the spot ink target to an industry specification:
Click the Conversion icon
Image Removed.Click the Spot Inks tab and choose ISO Curve B (2004) 1 from the Target list.From the Curves Method list, choose Tonal Match.- In the Device Condition Response Update dialog, click Yes to update the spot ink curve in the device condition.
- Click Close to close the Device Measurements dialog. (Click Yes to save the chart, if you are prompted.)
Task 2: Define the spot ink target to align to an industry specification (SCTV)
- Click the Calibration icon
Image Addedin the link connector between the CMYK Reference and the Offset Press panels. - Click the Redefine... button at the bottom left of the Calibration Edit dialog
- Click the Spot Inks tab and Target: Linear will be selected. Leave this value as is.
- The ISO definition specifies that Curves Method must use Linear SCTV, so all other method choices are disabled.)
- Click View Curves... to open the Calibration Curves dialog box and verify your curve.
- Click the Spot button at the top left of the panel.
- From the Spot ink list choose Pantone 123.
- View the Pantone 123 spot ink channel in the graph.
- Click Close
- Click OK to update the print calibration curve and add the spot color curve channel.
For this exercise, we will not output the Tint Ramp chart to VPS and measure to confirm the calibration values were correctly applied, as VPS is unable to measure raster files using SCTV. You can only measure SCTV from a printed spot ink using an SCTV-enabled spectrophotometer.
Click OK.The print calibration curve is re-generated to match the spot ink target.Outcome
You have added a custom spot ink channel to a print calibration curve and aligned the printed appearance of the spot to Linear SCTV.