Creating accessible PDF documents

Accessible PDF Transform feature (HTFA124) is a separately priced feature for the AFP to PDF transform.

When HTFA124 is installed, you can create accessible PDF documents by using the AFP to PDF transform.

A growing number of governments and corporations require electronic documents to be accessible for people with disabilities. Accessible PDF documents can be designed to assist a visually impaired individual to browse PDF document contents by using assistive technologies. An accessible PDF document contains specific and mandatory tagging techniques to enhance the navigation of the document.

An accessible PDF has two compliance types that conform to the ISO standard 14289:

PDFUA compliance: An accessible PDF with PDFUA compliance embeds all fonts within the PDF to improve document fidelity.
WCAG compliance: An accessible PDF with WCAG compliance allows the Adobe™ Base 14 fonts to be mentioned by name instead of being embedded in the PDF document, which can reduce the PDF file size for quicker loading by the web browser.

Accessible PDF documents can be viewed as normal PDF documents by using the common viewers like Adobe. However, when used with assistive technology, the tagged content allows a visually impaired user to navigate the document content using the assistive technology interface.

Producing accessible PDF documents

Creating an accessible PDF document is achieved through a process of adding tags and other accessibility features to a document. Tags and other features identify unique attributes of content such as text, tables, graphics, lists, charts, and others. Page content navigation information and reading order are also identified within these tags, allowing assistive technologies to help browsing the document contents and present the content in a logical and easily understandable order. This includes being able to skip sections of content that aren't of immediate interest, and the ability to move forward and backward through the document easily. Tags also identify the heading and row descriptions so that the content of tables can be properly communicated, again enabling quick and easy navigation. After tagged, the resulting accessible PDF documents contain the tags and other special content within the underlying document structure and are used by assistive technologies.

The Accessible PDF Transform allows organizations to avoid manual tagging by automatically converting high-volume transaction and variable content print production files into PDF/UA format. The AFP to PDF transform can create PDFUA-compliant accessible PDF documents or WCAG-compliant accessible PDF documents. The automatic tagging of the input document requires a special input control file that is called a User Accessibility Control File (referred to as the ICF in this and other documents). The ICF file contains business rules that instruct the Accessible PDF Transform to look for specific text strings, images, objects, and more in the input, and if found, insert a specific tag for that object in the PDF output. The ICF file name can be specified on the transform command by using the pdf-user-accessibility-control-file job attribute.

For more information about the pdf-user-accessibility-control-file job attribute, see Job attributes for creating accessible PDF documents.

An ICF file is created by the customer for each individual document or more likely, a group of like documents. Depending on the format of the input document, ICF files can be complex to create. Installation of Accessible PDF Transform entitles you to a single license of Crawford Technologies Inc. Pro Designer GUI. This product runs on Windows™ and provides an easy to use WYSIWYG interface to assist you in creating ICF files from corresponding input. You must contact Crawford Technologies Inc. to obtain your Pro Designer software and license key. For more information, see the /usr/lpp/IBM/PrintXform/V1R2/samples/accessible_ReadMeFirst.txt file.

The following two manuals are included with the Accessible PDF Transform and can be used to assist with the generation of Accessible PDF output, including creating and editing ICF files.

Accessible PDF Transform User Guide is in /usr/lpp/IBM/PrintXform/V1R2/samples/accessible_PDF_UserGuide.pdf.
Accessible PDF Transform Reference Guide is in /usr/lpp/IBM/PrintXform/V1R2/samples/accessible_PDF_ReferenceGuide.pdf.
Note: Creating accessible PDF documents by using the AFP to PDF transform results in increased CPU consumption and larger output file size.

Note: When creating accessible PDF documents with encryption, ensure that the pdf accessibility flag is enabled. Do not choose 'all' or 'copy' if using the pdf-protect job attribute. Do not choose 'select' if using the AOP_PROTECT environment variable. Another option is to use allowaccessibility with the AOP_PROTECT_EXTENDED environment variable.

Example for creating an accessible PDF document

To transform an AFP file myfile.afp to a PDF/UA compliant accessible PDF myPDFUA.pdf, enter the following command on one line: afpxpdf –o myPDFUA.pdf –c pdfua -j " pdf-user-accessibility-control-file='myfileAccPDF.icf' pdf-title='PDF UA Title' " myfile.afp

The example assumes myfileAccPDF.icf exists in the /usr/lpp/IBM/PrintXform/V1R2/samples directory, and that you have a transform class that is defined with following entries:

transform afpxpdf_pdfua
   start-command = afpxpdfd
   min-active = 0
   max-active = 2
   maximum-idle-time = 300 # 5 minutes
   environment = {
      ................................
      AOP_ACCESSIBLE_COMPLIANCE_TYPE -> 'pdfua'
      AOP_PDF_LANGUAGE -> 'En-US' 
      AOP_UACF_LOCATION –> "/usr/lpp/IBM/PrintXform/V1R2/samples”
      _BPX_JOBNAME -> AFPXPDFD
    } ;

Note: The use of AOP_UACF_LOCATION is important to specify the path where the *.icf file is located.