8 CalibrationThe vDot4 plugin is supplied with a number of calibration curves for specific media and resolution.These curves are created with reference printers of the same type that the plugin is intended tosupport.In many cases printers will have characteristics so similar to the reference printers that no additionalsteps are needed to get good quality output. However, it can be helpful to calibrate your printer tocompensate for differences between it and the reference... 8 CalibrationThe vDot4 plugin is supplied with a number of calibration curves for specific media and resolution.These curves are created with reference printers of the same type that the plugin is intended tosupport.In many cases printers will have characteristics so similar to the reference printers that no additionalsteps are needed to get good quality output. However, it can be helpful to calibrate your printer tocompensate for differences between it and the reference machine.8.1 Tools and materialsThe RIP includes facilities for interfacing an automatic strip reading measurement instrument such asthe X-Rite DTP-41. However, for occasional calibration you can also use any quality instrument capableof reading color densities in Status T format.Note: The DTP-41 is not only able to measure color densities required for calibration, but it is also aspectrophotometer which is a required to create ICC profiles.You will require a good supply of media. Note that the RIP can only be calibrated for media listed inAppendix A, “Inks and media”—for which Global Graphics provides internal calibration targets. Tocreate an initial calibration curve for other media types requires the use of additional tools not providedwith the vDot4 plugin.8.2 Printing a targetThis step is essential and cannot be omitted.Start by ensuring that you have created a Page setup with the correct settings for the calibration targets.The Color drop-down menu box will display vDot4 and Calibration should show None. Thisexample describes how to calibrate an Epson 7890 using Epson Standard Proofing Paper at 720 dpi. Asuitable Page setup called 7890 Color vDot is created for this purpose.1. Select Output > Print Calibration. The following dialog ia displayed.Figure 12 Print CalibrationOKI PCL PLUGINCONTENTS 14CONTENTS 142. Highlight the correct Page setup, and click Print uncalibrated target. The RIP will generate a specialfour-color target which you should print on the correct media type.8.3 Measuring the targetOnce the target is printed it must be measured.8.3.1 Using GenlinIf you do not have a strip-reading densitometer such as the DTP-41 supported by Genlin, and youwish to use a manual Status T densitometer, skip this section and go to “Entering measurement data”on page 15.1. If you have the DTP-41 or similar instrument, use the Genlin application installed with your RIP.Locate the Genlin application (genlintool.exe) inside the RIP folder and launch it.2. Select File > Configure from the menu bar. To display the following dialog:Figure 13 Genlin Configuration dialog3. Use the Change button to locate the RIP you are calibrating. Highlight the SW folder within theRIP folder before clicking OK.4. Use the Instrument drop-down to select the correct model of your measuring device.5. Set Measure to Status T,6. Set Media to Press Paper.7. Set the Port to the serial port to which you’ve connected the measurement device.8. Click OK to close the configuration dialog.9. Select File > Read Target. A box with one or more Reference Numbers is displayed. Each time theRIP generates a calibration target it records the details in a database and gives each target a ReferenceNumber. This number is printed on the target. Check the target printed in “Printing a target”on page 13. Note the Reference Number and highlight the correct number in the list. Thenclick OK.10. Verify in the next screen that Genlin is expecting to read the correct number of colors for this target,and click Read. For each color strip, Genlin displays a confirmation prompt.11. Arrange the target in the direction of the arrow with the first (Cyan) strip under the measuringhead and slide the target under the head until it stops. Click OK and feed the target gentlythrough the reader.12. Repeat this process for each of the four colors, after which Genlin will display a message indicatingthat the RIP may now import the linearization data. Click OK.13. Genlin has placed a file of measurement data in the RIP folder ready for the RIP to import.OKI PCL PLUGINCONTENTS 15CONTENTS 158.3.2 Entering measurement data1. From the Harlequin RIP select Output > Calibration Manager. The following dialog appears:Figure 14 Calibration Manager2. In the Device drop-down menu, select the device that you are calibrating. This must be the samedevice name as was selected in Page setup when you printed the Calibration Target.3. Click New. The following dialog appears:Figure 15 Edit calibrated target dialogProfileUse this drop-down to select the same Calibration profile that you chosein Page setup, which must match the media. This underlying Calibrationprofile provides the target information (aim curve) against whichyou will calibrate the printer.NameEnter a convenient name for this calibration set.OKI PCL PLUGINCONTENTS 16CONTENTS 16ResolutionCalibration is only accurate at one resolution, so select the same resolutionas selected in Page setup. A warning is displayed in the RIP monitor,should you attempt to use it at a different resolution.8.3.3 Entering measurement data—manualIf you are using a hand-held densitometer make sure it is set to the Status T response curve.Measure the density values for each Cyan patch on the target and enter these values in the boxes.When you have finished entering the Cyan data, select another color in the Channel drop-down, andrepeat until all four sets of values have been entered. When completed click OK.8.3.4 Import data from strip readerIf you used Genlin to create an import data file as described in “Using Genlin” on page 14, and clickthe Import button.The Import Measurements dialog box shows a list of the four color channels contained in the importdata file. Click Import.The RIP will immediately import all the data values and change the numbers in all the boxes for allfour colors. Click OK to save the Calibration set. ai giúp mình với
Xem thêm.