CIB pdf toolbox technical guide (EN)

5.1. Recommendations and hints

General
Form fields in PDF
PDF/A and encryption
Signatures in PDF/A
PDF content as image in PDF/A
Embedding attachments in PDF/A-3

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General

Below are some "best practices" and tips for converting PDF files to PDF/A files.

When creating PDF/A files from existing PDF files, you must always consider which properties of PDF files are permitted by the corresponding PDF/A specification (ISO 19005-1, ISO 19005-2, ISO 19005-3).

Examples:

• When converting to PDF/A-1b and PDF/A-2b, attachments in PDF files are not transferred to PDF/A, they will be removed.
• JavaScript elements inside of PDF files are generally removed.

Form fields in PDF

When converting to PDF/A, the fonts used in the PDF file are embedded in the created PDF/A file. If form fields with content are contained in the PDF file, all of the associated fonts are embedded in the result document. This can increase the file size considerably.

Um In order to embed only the used characters in the associated fonts in the output document, we recommend setting the "FlattenFormfields" property to the value "1". The visual representation of the form fields is retained, the form field itself is removed. For further information, please have a look at chapter Removing form fields but keeping the view.

PDF/A and encryption

When converting to the PDF/A archive format, encryption is generally removed. Further information on encryption and password protection can be found in chapter Passwords and ecryption with PDFs.

Signatures in PDF/A

Currently, signing is only supported for the versions PDF/A-2b and PDF/A-3b. Detailed information about signing PDFs can be found in chapter PDF signature with certificate.

PDF content as image in PDF/A

With the property „ImagePdfCreation“ can be used that the pages of a PDF file to be converted are written to the PDF/A file as graphics via CIB renderer

Hint:

When the pages are embedded as graphics in PDF/A, a text search on these pages is not possible. By additionally setting the “ImagePdfCreationPreserveText” property, it is possible to ensure that text contents that are present in the input file are still transferred to the output file using the HOCR export.

When displayed as a graphic, this also affects the file size of the created PDF/A file. The resolution of the graphics is set to 150 DPI by default. Adjustments are possible via the "TiffResolution" property.

Handling errors with PdfAFallback

In case that elements of a PDF page cannot be converted to PDF/A, an error message is displayed. To create a valid PDF/A document anyway, the "PdfAFallback" property can be set. The property is used to control that in such a case the page concerned is automatically converted into the PDF/A file as an image using the CIB renderer. The possible transfer parameters are listed in chapter Specific options for PDF/A.

Embedding attachments in PDF/A-3

The archive format PDF/A-3 permits embedded files (file attachments). Additional descriptions of the embedded files can be specified using the values of the "EmbeddedFiles" property (see chapter Special options for PDF join).