"Generation of inspection data" option
Prerequisite: An Inline sheet inspection system such as HEIDELBERG Prinect Inspection Control 4 must be available on the press in order for this option to display in a SheetfedPrinting sequence template, and the respective license must be enabled. In addition, any additional software components that may be required must be installed on the press and on the Prinect server. To generate inline reference images in a Prinect Production system configuration with Prinect Prepress as the prepress system, the "Generation of inspection data" option must be enabled in the respective upstream imposition output sequence. See "Generation of inspection data" Option. Prinect applications "Inspection Toolbox" and "PDF Toolbox" may also be required for the various inspection procedures.
You can use the following sheet inspection procedures:
•Production Inspection
Production Inspection is performed on the running press equipped with an inspection system. The printed sheets are continuously scanned with the camera of the inspection system (Prinect Image Control or Prinect Inspection Control) and these image files are compared with a "digital reference sheet." Production Inspection allows any printing errors that may occur during printing – e.g., deviating color densities – to be detected and automatically corrected.
•PDF Inspection:
PDF Inspection is performed with Prinect Inspection Toolbox. For PDF inspection, a full-sheet image in PDF or TIFF format generated in the prepress system is used as a "digital reference image". For each inspection process, a press sheet generated during printing is scanned with the inspection system's camera, and this image file is transferred to the Prinect Inspection Toolbox, where it is compared with the reference image. PDF inspection checks and ensures that the content of the print job matches the content of the customer job.
•Sheet Inspection:
Sheet Inspection is performed with Prinect Inspection Toolbox. To do this, a sheet printed at the start of the printing process is scanned by the inspection system's camera, and this image file is used as a "digital reference image". For each inspection process, a press sheet generated during printing is scanned with the inspection system's camera, and this image file is transferred to Prinect Inspection Toolbox, where it is compared with the reference image. Sheet Inspection lets you detect permanent print image faults that are caused, for example, by defective plates or blankets.
The option "Generation of inspection data" is necessary for Production Inspection. Production Inspection inspection enables continuous quality control of color reproduction on the press during printing. To do this, the press sheets are scanned by the inspection system's camera as they pass through the press. The color densities of the printed colors in the different areas of the press sheets are then measured and the measured values are compared with the corresponding values of a "digital reference sheet". The inspection system uses two files for this comparison: a "reference image" (digital reference sheet) and an "inspection level file." The inspection level file defines the inspection accuracy for different areas ("inspection levels") of the press sheet or for the entire press sheet. The "digital reference sheet" is automatically generated on the sheet inspection system after the good sheet counter is switched on by averaging the full sheet images first scanned by the camera. The reference image and the inspection level file must be available on the inspection system in PNG image format.
This means the reference image represents the "ideal reference", i.e., the desired target state that the press sheets should match as close as possible, which is verified by measuring the sheet scans taken with the inspection system's camera. Any deviations found are used for automatic ink zone readjustment of the press. The deviations found are also transferred to the Prinect Customer Portal as "reports" and logged there in the "Inspection" view of the "Insights" app.
The inspection level file defines the test accuracy with which the comparison between the measured press sheet and the reference image is performed. Different accuracy levels known as "inspection levels" for the check can be defined for a press sheet as a whole or for different areas of the press sheet, The Prinect workflow supports up to five inspection levels, with level 1 representing the highest and level 5 the lowest inspection accuracy.
Generating reference images and inspection level files for Production Inspection
The reference images and inspection level files are generated at different points in the print shop workflow. A distinction must be made here between a Prinect Production configuration with Prinect Prepress Manager as the prepress system and a "mixed" configuration with a third-party prepress system and Prinect Pressroom Manager.
Creating reference images
Production Inspection requires reference images in the PNG format. The reference images are generated from images captured by the inspection system after the good sheet counter is turned on.
Generating Inspection Level Files
Inspection level files determine the accuracy of the inspection that the inspection system performs on the press sheets. The inspection accuracy is defined in one of 5 "inspection levels." In the inspection level file, the inspection levels are represented by different shades of gray. A separate color separation is created for each inspection level and added to the PDF sheet file. Inspection level files either define the inspection accuracy for an entire sheet by assigning only a single inspection level to each sheet, or they contain different inspection levels for individual areas of the sheet content that define how accurately the inspection system should check the respective areas. Inspection level files are generated in the following locations:
•In a Prinect Production configuration, the inspection level files are prepared in the ImposePDF sequence by adding the necessary additional inspection level color separations to the processed PDF files. To do this, you must create a new ImposePDF sequence (see "ImposePDF" Sequence Template) and make the following settings:
aEnable all the options in "Color Usage".
bOpen the "Marks Replacement" options area and enable the "Remove All Marks" option. This will hide all mark layers for the generated inspection areas.
cIn the "Color output" list box, select the "Only Inspection Level Colors" item. With this selection, only colors with the names "InspL_1," "InspL_2," etc. are used for the inspection level files.
dIf you want the inspection levels to be generated automatically with the ImposePDF sequence, select the inspection levels to be used for inspection level generation from the "Create inspection level automatically" drop-down list.
If you want to create the inspection areas individually with the Coating Editor of Prinect PDF Toolbox, select "None".
•In a Prinect Pressroom Manager configuration with a third-party prepress system, the prepress system generates an inspection level file in PDF format for each printed sheet and submits it to Pressroom Manager. See also Import of inspection data from an external prepress system. These PDF files are converted to the PNG image format by the SheetfedPrinting sequence if the "Generation of inspection data" option is enabled in the SheetfedPrinting sequence.
•In addition, specific areas with different inspection levels can be defined manually in the PDF sheet files. This can be helpful if the press sheet contains "critical" areas that need to be checked particularly thoroughly, while other areas of the sheet need to be checked less thoroughly. This distinction helps to prevent false positives. The Coating Editor in Prinect PDF Toolbox can be used to create individual inspection level areas. Basically, a separate color separation is created for each defined inspection level and added to the PDF documents. In these color separations, the defined inspection level areas are shown as gray areas. Each inspection level is assigned a specific gray level density (in %). See also Manual definition of inspection areas with the Coating Editor in PDF Toolbox.
Submitting the inspection level files to the inspection system
The inspection level files are transferred to the inspection system via the network connection between Prinect server and Press Center. In this way, the reference images are also submitted to the inspection system if the reference images are not generated with the inspection system.
Configuration of color options
Correctly set color management is required to compare the colors measured by the Inspection System with the colors of the reference image. See also "Color Conversion" option. The following elements are required:
•The standard ink profile for printing
For printing, a CMYK press profile is required, for example a profile adapted to region-specific print processes (SWOP, EURO etc.). Click "Browse" to select a press profile. See "Default Press Profile" box.
•If applicable, a PDF/X output intent if a PDF/X output intent is embedded in the document PDF file of the print job.
In some cases, a "PDF/X output intent" is defined in the PDF documents of the print job. You can then enable the option "Use Embedded PDF/X Output Intent, if Available, as Press Profile". The PDF/X output intent is then used as the ink profile for printing instead of the set default press profile. See "Use Embedded PDF/X Output Intent, if available, as Press Profile" option.
•The color profile for the camera of the Inspection system
An RGB color profile representing the color characterization of the camera is required for the camera of the Inspection System. Click "Browse" to select a suitable camera profile. See "Camera profile" box.
A "Browse" dialog opens when you click "Browse". In this dialog, go to folder "[Prinect Server]\PTConfig\SysConfig\Resources\ICC-Profiles\Printer" The press profiles for various offset standards are located in further subfolders. Go to the appropriate subfolder and select the default profile for offset printing. See also "Press Profile" group.
"Use Embedded PDF/X Output Intent, if available, as Press Profile" option
If enabled, this option affects the default press profile.
•The system behaves as follows if this option is enabled:
•When a PDF/X file with an embedded ICC profile as its Output Intent is edited, the embedded press profile is used for color space conversion. The press profile set in "Press Profile" is ignored.
•If there is no Output Intent, the ICC profile set in "Default Press Profile" will be used.
•The press profile set in "Default Press Profile" is used for color space conversion if this option is not enabled.
Any embedded PDF/X Output Intent will not be used for color space conversion during output.
This option should be enabled whenever an embedded PDF/X output intent is used in addition to the color management of the print output. This is recommended because a PDF/X output intent usually more accurately represents the intended color settings for the output than a default print profile.
Prerequisite: The camera profile matching the Inspection system must be located in the following Prinect Server path: [Prinect Server]\PTConfig\SysConfig\Resources\ICC-Profiles\Camera.
A "Browse" dialog opens when you click "Browse". In this dialog, go to folder "[Prinect Server]\PTConfig\SysConfig\Resources\ICC-Profiles\Camera" and select the camera profile for the Inspection system.
Note: If a third-party prepress system is operated with Prinect Pressroom, the selection of a camera profile at this point does not affect color measurement, i.e., you need not select a camera color profile in this case.
Import of inspection data from an external prepress system
If Prinect Production Press is connected to a third-party prepress system, the generation of the inspection files and the forwarding of the preview images and the data for ink zone control to the press are parameterized in the SheetfedPrinting sequence. In this case, the reference image and, if necessary, the inspection stage file must be generated from the sheet PDF files supplied by the prepress system. The procedure is as follows:
•From the external prepress system, the sheet PDF files are stored in a hotfolder on the Prinect server computer and "fetched" from there for further use in Prinect Production Press. These files are used to create the reference images and, where applicable, to create the inspection level files with the Coating Editor of Prinect PDF Toolbox.
•Running in the background, a special Prinect module, "Prinect Preview Service" creates the reference images directly from the sheet PDF files. This function is activated by switching on the "Generation of inspection data" option in the SheetfedPrinting sequence if an external prepress system is connected. The reference images are generated as composite images in PNG format.
•The inspection level files are generated - just as in a configuration with a connected Prinect Prepress Manager - with the Coating Editor of Prinect PDF Toolbox on the basis of the sheet PDF files supplied by the prepress system. See Manual definition of inspection areas with the Coating Editor in PDF Toolbox.
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