6.0 Best Practices For PDF Creation
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Adobe Portable Document Format (PDF) is an open standard (known as ISO 32000) for distributing electronic documents. This universal file format preserves the exact look and feel of any source document, including all of the fonts, formatting, colors, and graphics, regardless of the application and platform used to create it. Adobe PDF files can be opened reliably across a broad range of hardware and software with the free Adobe Acrobat Reader® software (http://get.adobe.com/reader/). Additionally, some cell phones (e.g., iPhone) and electronic book readers (e.g., Kindle) enable PDF viewing. Best practices for creating PDFs involve making PDFs that contain a variety of features that make them user friendly, including accessible to users with disabilities.
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6.1 Uses of PDF Format
Because PDF files look like original documents and preserve source file information - text, drawings, maps, full-color graphics, photos, etc. - they are excellent for presenting and distributing digitized content. PDF documents can be made full-text searchable and also work with assistive technology, making them accessible to users with disabilities. The Library commonly uses the PDF format as one of its access formats for textual print resources that it digitizes.
6.2 Required Features
All PDFs of digitized textual content from the Library's collections should include the following features:
- Accessibility features-PDF documents should be tagged, a feature which makes them readable by screen readers and keeps page content in a logical reading order. PDFs made with Adobe Acrobat should have the "Make Accessible" option applied to them. PDFs made with ABBYYFineReader and other applications should have the "enable tagged PDF" option applied during their creation. Adobe Acrobat has functionality by which you can test PDF files for accessibility. PDFs containing text should be made full-text searchable. Searchable PDFs should be saved with the "text-under-images" option.
- PDFs should begin with a document source information page that informs the reader that, at the very least, that the University of Illinois Library created the PDF document and the year the document was created.
- If PDF is the only format being created (e.g., if a document has been scanned to PDF format with no initial archival image files being created), two versions should be made-a low resolution format for web viewing and a high resolution PDF/A. (See below).
- PDFs used for access purposes should be optimized for fast web viewing. Optimizing PDF files for the Web can significantly shrink their size and boost display speed, saving bandwidth and user frustration, and can be distributed efficiently. This can be done most easily by utilizing Fast Web View option when saving an access PDF. Fast Web View option structures a PDF document for page-at-a-time downloading from the WWW. It compresses text and line art, making for faster access and viewing when downloading the file from the web or a network. With page-at-a-time downloading, the web server sends only the requested page, rather than the entire PDF document. This is especially important with large documents that can take a long time to download from a server.
- PDFs should be made compatible with earlier versions of Adobe Reader back to version 5.0. Not all users are guaranteed to have the most current version of the reader.
- Access PDFs should be made without any features that secure or lock access to the content.
6.3 Additional Good Features That Are Recommended If Time Permits
- The "make accessible" option automatically tags a document; tags can be edited if not assigned correctly by the program and additional tags can be added. This requires additional human intervention.
- Bookmarks are navigational links listed in the Bookmarks panes in Adobe Acrobat and Adobe Reader that display specific page content in the Document pane when clicked. Bookmarking a PDF require additional human intervention.
- Initial view settings can be set to insure that the PDF always opens in a particular layout or view.
6.4 Archival PDFs
If master image files have been created and preserved, PDFs can be created from them and optimized for web access. However, if PDF is the only format being created (e.g., if a document has been scanned to PDF format with no initial master, or archival, image files being created), a high resolution PDF/A should be made in addition to the low resolution format for web viewing.
PDF/A-1 is a constrained form of Adobe PDF version 1.4 intended to be suitable for long-term preservation of page-oriented documents. All of the information necessary for displaying the document in the same manner every time is embedded in the file. This includes all visible content like text, raster images, vector graphics, fonts, color information and much more.
The PDF/A format attempts to maximize:
- Device independence
The constraints include:
- Audio and video content are forbidden
- All fonts must be embedded and also must be legally embeddable for unlimited, universal rendering
- Colorspaces specified in a device-independent manner
- Encryption is disallowed
- Use of standards-based metadata is mandated
 PDF/A-1, PDF for Long-term Preservation, Use of PDF 1.4 (Library of Congress, Sustainability of Digital Formats website: http://www.digitalpreservation.gov/formats/fdd/fdd000125.shtml)
7.0 Descriptive Metadata
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