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Website Style Guide:
Chapter 3: File Format

This chapter is draft: Want to comment? Contact Lois Nilsen, DHHS Web Manager.

Choosing the Right Format | Conveying Alternative Formats | PDF Accessibility | Planning for Disabilities | Miscellaneous PDF Information | Style Guide Home

3.1 Choosing the Right Format

In general, web pages in the NC DHHS site should be in industry standard formats (HTML and XHTML are current examples). These are open, industry standard web formats that do not impose an unnecessary burden on the intended audience.

Presenting documents in open, industry standard formats allows every person with a browser to read the documents. Further, it makes the documents easily retrievable using web search engines. Usability studies have shown that visitors can become frustrated and are less likely to access information that requires downloading with additional software or plug-ins, even if that software is freely available, because it involves extra time and effort to view the material. In addition, many proprietary files are so large, compared to industry standard formats, that visitors with slow connection speeds cannot download them. Certain software and plug-ins also pose difficulties for people with (primarily) visual impairments.

By providing documents in formats that most of the audience can use, you promote equitable access to the information and services.

3.1.1 PDF

Use Portable Document Formats (PDF), such as Adobe Acrobat, only as an alternate format to industry standard formats and only when there is a clear business need to use this format.

For example, PDF format is an appropriate format when it is important to retain the original formatting of a document, such as forms. Long formatted documents (more than 5-10 print pages) may require PDF.

PDF has many disadvantages and so should not be overused:

  • Inaccessibility. Screen readers often cannot read PDF files. Unless the person who created the original file is very savvy on accessibility issues, and unless the end result has been tested for accessibility, assume that the Acrobat file is inaccessible to anyone with vision problems.
  • Readability: PDF was designed for print and can be hard to read on screen. Content is optimized for letter-sized sheets of paper, not for display in a browser window. The command to make text larger or smaller works differently, as does the search function, which confuses visitors.
  • Navigation: PDF pages lack navigation that help visitors get to other pages in your site. When search engines do pick up a PDF page, they have no navigation alternatives or way of knowing what else is offered on the site.
  • Viewer Requirements: PDF viewers are not embedded in some Web browsers. PDF viewers require more powerful hardware for on-line viewing than a Web browser alone.

3.1.2 Proprietary File Formats (such as MS Word, Excel, PowerPoint)

Avoid making documents available only in proprietary formats that require purchase or licensing of commercial software (for example, MS Word, MS PowerPoint). If you believe these formats are warranted because the intended use is data analysis or manipulation, ensure that the entire intended audience is known to have ready access to the appropriate software or provide a link to download the appropriate viewer or plug-in. If providing a document in proprietary format, also offer it in a nonproprietary format.

Only provide a link to a plug-in or viewer once per page.

3.1.3 Best Practices when linking to PDF or other Proprietary Files

When linking to a document in an alternative format (such as PDF or MS Word), include a text description of the document, including the name, file type, file size, and effective date. This will ensure that visitors have a reasonable understanding of what to expect when they view the material and that search engines can easily find it.

Provide a link to the downloadable free viewer.

To ensure maximum accessibility, also provide a version of the document in an industry standard format, such as HTML, or ensure the document has passed all accessibility checks in Acrobat Professional. This is a DHHS requirement when the intended audience is the people served by DHHS.


3.2 Conveying Alternative Formats

When providing a document in an alternative format, use the file extension to connote which format is being used, and provide the file size. The link should be the title, not the file information.


  • Title (File extension in all caps, file size)


  • Medicaid Annual Report (PDF, 2 MB)

When listing a PDF’s size in megabytes, use decimals. When listing in kilobytes, round up rather than using decimals. (2) The abbreviation for megabyte is MB, while the abbreviation for kilobyte is KB.


  • A Consumer’s Guide to North Carolina Medicaid Health Insurance Programs for Children and Families, (PDF, 6.45 MB)
  • DHHS Informal Appeal Request Form, (PDF, 54 KB)

When providing a document in more than one format, use the following convention, with the links being the name of the format.


  • Title of Document:
    • Format (File extension in all caps, file size)
    • Format (File extension in all caps, file size)


  • List of Licensed Facilities:
    • Text format (Text, 788 KB)
    • Self-extracting format (EXE, 870 KB)
    • Compressed format (ZIP, 802 KB)
    • Comma-delimited format (CSV, 1 MB)
    • Portable document format (PDF, 6 MB)
    • Microsoft Word (DOC, 500KB)

To easily learn the size of a document, use the Firefox add-on: "Get File Size."


3.3 PDF Accessibility

Ensuring accessibility for the disabled in PDF files can be difficult. Recent versions of Adobe Acrobat come equipped with a screen reader for the visually impaired, but screen readers such as the one that comes standard with Adobe Acrobat will only work properly if the PDF document has been properly tagged.

3.3.1 Tagging Documents

Acrobat 7.0 and above automatically analyzes a document’s logical structure and creates a new version that approximates the original structure and reading order. In most cases, this file will translate better with a screen reader than an untagged file will. You can also use this tool in conjunction with the Acrobat 7.0 or above batch processing function to convert volumes of documents efficiently.

Remember to always provide alternative text for any graphics in your source document.

The basic steps for tagging a document:

  1. Open the PDF
  2. The Description pane of the Document Properties screen (File Menu) will tell you if the document is tagged or not.
  3. If it isn’t, close that screen. Go to the Advanced menu and choose Accessibility -> Add Tags to Document
  4. Run a full accessibility check from that same menu.
  5. If the checker reports any problems, open the tags palette (View -> Navigation Tabs -> Tags). Use the disclosure triangles to step through your document’s new tag structure. You’re better off if you select Highlight Content from the palette’s Options menu, as Acrobat will then draw a hard-to-see border around the object whose tag you select.

Use the latest version of publishing tools that support accessibility features. The latest versions of Word, InDesign, PageMaker, and Quark create better-tagged Adobe PDF files, which have greater functionality for accessibility, than the structured Adobe PDF created from older versions of software.

Define a logical reading order for your document. Logical reading order, or logical structure, refers to the organization of a document, such as the title page, chapters, sections, and subsections. This logical structure provides a mechanism to indicate the precise reading order and improve navigation, particularly for longer, more complex documents. In addition, when viewing a tagged Adobe PDF file in which the logical read order has been clearly defined, a user can use Acrobat’s Reflow feature to zoom in to any portion of the document and the text will automatically re-flow to fit the available screen space.

Use application-based styles to format text and define and create document structure such as titles, chapters, headings, and paragraphs. Styles provide structure information when you create a tagged Adobe PDF file. For example, do not use the Enter key to add space between paragraphs. Instead, use the “Spacing Before” and “Spacing After” paragraph properties to achieve this effect.

Create column layouts using your application’s column layout feature. Don’t use tabs to simulate double-column text. For example, if a document has been correctly authored using two columns to create a two-column format, the screen reader knows it should read all the way down the first column and then proceed to the second column. On the other hand, if the writer used tabs to imitate the look of two-column text, the screen reader would simply read horizontally, going from the first line in the first column and then tabbing over to the first line in the second column.

Create tables using your application’s table creation feature. Don’t use tabs or graphics to create a table. It is also helpful to use table formats in the authoring application, such as table column heading, row heading, table cell data, etc.

Avoid complicated table structures using merged and split cells, and nested and combined tables to produce a desired layout. Avoid using tables for layout purposes. Complex tables are difficult to impossible to export accessibly, and you will end up spending hours re-tagging your tables in Acrobat.

Use Unicode text, which is a standard for describing text characters. This ensures that all characters and words are presented to assistive technologies in a clear and understandable manner. Unicode also differentiates between soft and hard hyphens. As a result, a hyphenated word that spans two lines, such as “com-puter,” can be read as a single word.

Embed all fonts when creating a PDF file from your publishing application. This will allow for touch-ups that might become necessary in your final PDF file. If the font has been subsetted, you will not be able to edit the text from within Acrobat.

Group complex illustrations. If you created an illustration out of several smaller illustrations, use the Group command to group them into a single illustration.

Add alternate text to images. Include equivalent text descriptions for graphics, so that someone using screen reader software can understand the purpose of the graphics. Keep in mind that repeating images with long text descriptions will become very tiresome, so label accordingly. Some graphics are present to add color and visual appeal to a document. These document elements, which are referred to as artifacts, do not need alternate text since they are not adding to the message of the document.

Do not rely on color to convey information. If color is used to convey important information, an alternative indicator must be used, such as an asterisk (*) or other symbol.


3.4 Planning for Disabilities

In addition to tagging documents for the visually impaired, there are a variety of other disabilities that you must also consider. Planning for people with other disabilities should play a part in your document creation process.

3.4.1 Motor Disabilities:

Don’t make hot spots too small. Of course, the phrase “too small” is relative, and it is true that people can enlarge the document, thus enlarging the hot spots within the document, but use good judgment here. The smaller the link, the more difficult it will be for someone with limited fine muscle control to click on the link.

3.4.2 Hearing Disabilities

Provide transcripts for multimedia. If you embed multimedia objects with sound in your PDF documents, you will exclude both the deaf and the deaf-blind if you do not provide a transcript. Provide synchronized captions for video. People who are deaf need this if the video does not make sense when the sound is turned off.

3.4.3 Low Vision

Make sure there is enough contrast in the PDF document. Ensure that any information conveyed with color is conveyed equally well when color is not available. You may want to use a textual clue in addition to the color in order to convey the information.


3.5 Miscellaneous PDF Information

3.5.1 Types of PDF Files

PDFs come in three different types. These include image-only files, searchable image files, and formatted text and graphics files. In order to make content as accessible as possible, avoid the use of image-only files. Image-only files are the hardest of the three to transfer to Braille and the hardest to use a screen reading program on, as the text that appears in the file is actually a part of the image, rather than individually separated letters of text.

3.5.2 Testing PDF Tags

The best way to test that a PDF document that is already on the web has been tagged properly is to open the document in HTML format. To do this, run a Google search for the document you want to test. When you find the document, choose the link that says “View as HTML.” If the document has been properly tagged, the document should appear just as it did in PDF format. (1)

3.5.3 PDF Thumbnails and Bookmarks

Thumbnails and bookmarks should appear in PDF documents that are two or more pages in length to help encourage easy navigation. (2)

3.5.4 PDF Open View

All PDFs should be formatted so that they open as follows:

  • Magnification – Fit Width
  • Page Layout – single page

Thumbnails or bookmarks navigation panel open for PDFs that are two or more pages

3.5.5 Titles and Subjects

All title and subject fields should be filled in properly to help optimize the document for search engines.

3.5.6 Character Use

Use standard characters in PDFs whenever possible. People with visual impairments often rely on the use of “hot keys” rather than pointing and clicking with a mouse. Using standard characters will make it easier for disabled people to navigate the document.

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