Section Three: Enhancing On-Screen Viewing

This section provides step-by-step instructions on how to change the text color and background color of Portable Document Format (PDF) documents.

To enhance on-screen viewing of documents, use features such as:

Reflow
Form field hover colors
Automatic scrolling
Full screen

If you use screen magnification software with Adobe® Reader® 6.0, consult the screen magnification Help files for specific support for reading PDF documents.

You will need the following:

Adobe Reader 6.01 or later
A version of the screen magnification software that works with Adobe Reader 6.0.1 or later

Checking document accessibility

Before reading a PDF document, it is a good idea to check the anticipated accessibility of the document. If the document is not accessible, it may not be read at all or it may be read in the wrong order.

To use Quick Check, do one of the following:

Choose Document > Quick Check.
Press Alt + D for Documents, then Q for Quick Check (Windows only).

Setting on-screen enhancement preferences

To open the Preferences dialog box, do one of the following:

Choose Edit > Preferences.
Press Alt + E for Edit, then N for Preferences (Windows only).
Press Ctrl + K (Windows) or Command + K (Mac OS).

Note that if the JAWS for Windows screen reader is used with screen magnification software, there may be a key conflict with Ctrl + K. If this conflict is encountered, use the JAWS PassKey (Insert + 3) before pressing Ctrl + K.

When the Preferences dialog box opens, focus will be on the last category modified. Press the first letter of any category to quickly move to it. Press the Tab key to move focus to the options for the current category. In this case, press the letter A for the Accessibility category.

Accessibility category

By default, the document colors appear as the author defined them. Adobe Reader 6.01 lets readers replace the document colors, increasing the contrast between text and background. Windows users also have the option to adopt any Windows color scheme established by the operating systems accessibility options.

The following table shows the steps to change the document colors in Adobe Reader 6.0 when the Accessibility category is selected in the Preferences dialog.
Windows	Mac OS
Press Alt + R to replace document colors.	Press Tab to move to the Replace document colors check box.
This enables two options: Press Alt + W to use system colors, for example, a high-contrast black color scheme. Press Alt + C to choose text and background colors that provide the best contrast.	This enables two options: Press Tab to move to use system colors, for example, a high-contrast black color scheme. Press Tab to move to choose a text and background color that provide the best contrast.
Under Custom color, press: Alt + B to move to the background color palette, then press Enter to display the palette colors. Use the arrow keys or the mouse to choose a color. Alt + T to move to the document text color palette, then press Enter to display the palette colors. Use the arrow keys or the mouse to choose a color.	Under Custom color, press: Tab to move to the background color palette, then press Enter to display the palette colors. Use the arrow keys or the mouse to choose a color. Tab to move to the document text color palette, then press Enter to display the palette colors. Use the arrow keys or the mouse to choose a color.
Within the Replace Document Colors, are the options to: Replace only the color of black text (Alt + O). This the default. For all text to appear using customized colors, clear this option. Change the color of line art (Alt + L). This is the default. For line art images to retain their colors, clear this option.	Within the Replace Document Colors, are the options to: Replace only the color of black text (press Tab to move to this option). This is the default. For all text to appear using customized colors, clear this option. Change the color of line art (press Tab to move to option). This is the default. For line art images to retain their colors, clear this option.

The Accessibility category in the Preferences dialog box

Document or page mode settings (Reading category)

The amount of a PDF document that assistive technology holds in its memory buffer depends on whether Adobe Reader 6.0 is processing the entire document (document mode) or just a single page (page mode). If screen magnification is used, this preference may affect the way this assistive technology works. Consult the screen magnification vendor for recommended settings for this Adobe Reader preference option.

Background

When assistive technology is used, and an entire document is in the memory buffer, all of the assistive technology’s facilities can be used to navigate the document. For instance, some assistive technologies provide screen reader users with ways to obtain a list of links, navigate to the next active item, or find a word in the document. Screen reader users can use these tools on the entire document, which is much more efficient. This is “document” mode. Screen reader users are likely to be more familiar with the navigation tools of their assistive technology than the navigation tools of individual applications.

Some assistive technologies, such as screen magnification software, are only concerned with presenting the information that is visible on the screen. It is much faster if the assistive technology only receives visible information, so it doesn’t have to sort through all the parts of the document that are not visible (page mode).

If the PDF file is not tagged, the structure must be synthesized for the parts of the document that are sent to the assistive technology. For large documents it can take a very long time to synthesize the structure. Adobe Reader 6.0 limits the amount of time it spends per page, but for a document that is hundreds of pages long, the synthesis can still add up to a very long delay. During this time, assistive technology will not be responding and may appear to be hung. Because screen reader users won’t know how large the file is until it is opened, they may not know that this is what is occurring. And if screen reader users don’t want to read the entire document, they may not need to have all of it analyzed when it is opened.

Setting document or page mode

Document or page mode is controlled by options in the Reading category of the Preferences dialog box.

The default is document mode for documents of 10 pages or less, and page mode for documents larger than 10 pages. To use page mode, select the Deliver Data In Pages When Document Exceeds check box. If selected, specify the maximum size of the document for document mode. To always use page mode, set that value to one page. Because all documents are at least one page long, they would always use page mode. If document mode is preferred, analyzing very long documents can be avoided by setting this value to a suitably large page count, for example, 100 pages.

The Reading category in the Preferences dialog box

This preference can be changed at any time, and it will take effect immediately. If a document is being read in page mode and document mode is preferred, change the preference setting. The assistive technology will download the new information as soon as it is available. Adobe Reader users can also switch from document to page mode, but since the assistive technology will not read information in the Preferences dialog box until Adobe Reader 6.0 is done downloading the document, this feature can’t be used to cancel the analysis of a long document as it is loading.

The settings will be retained.

Navigating in page mode

It is necessary to use the tools in Adobe Reader 6.0 to navigate PDF documents when using page mode. Adobe Reader users also need to be aware that assistive technology only knows about the current page. At the bottom of a page, advance to the next page by using the Reader commands (for example, Page Down or Ctrl + Page Down to advance to the next page).

To navigate to locations in the document or the table of contents, use Bookmarks in the Navigation pane. Advance to the next active item (form field, link, etc.) with Adobe Reader 6.0 by using the Tab key. However, you should make sure that these keystrokes are interpreted by Adobe Reader 6.0, not by the assistive technology software.

When in page mode, screen reader users may receive a message that indicates that the document is empty, even though there is text in the document. Adobe Reader 6.0 provides this message when it detects an empty page. If page mode is used, note that the message only applies to the current page, and that the next page may contain information. Advance to the next page to confirm this.

Setting read order options (Accessibility category)

Left-to-right, top-to-bottom reading order and Use reading order in raw print stream are much faster than Infer reading order from document. If one of these choices is selected, Adobe Reader users may want to use document mode all of the time, or may want to set the threshold to a very large document size. Use caution when using Infer reading order from document even though it is the recommended setting.