AMITIAE - Friday 17 October 2014

System Preferences in OS X 10.10, Yosemite: Accessibility

apple and chopsticks


By Graham K. Rogers


There have been a number of changes to System Preferences in OS X 10.10, Yosemite. Accessibility provides settings aimed at assisting the disabled. With the latest version of OS X, these settings have seen some slight changes with the addition of a Media sub-section, one extra item and some minor reorganisation. Most of the other settings are unchanged.

Before Mavericks, Accessibility was known as Universal Access. In the current version there are now four areas of assistance: Vision, Media, Hearing and Interacting. The functions are displayed in a window to the left. There are 10 items.

  • Vision: Display, Zoom and VoiceOver.

  • Media: Descriptions (new) and Captions.

  • Hearing: Audio.

  • Interacting: controls Keyboard, Mouse & Trackpad, Switch Control and Dictation: the previous Speakable Items has been removed. Switch Control has a number of useful ways to control a computer from external devices and has been simplified from the earlier version, but may still need some careful examination.

As each item in the left side window is highlighted, so controls are shown in the main panel. At the bottom of every pane is a singel checkbox: Show Accessibility status in menu bar. As well as the icon, a scrolling text is shown for a short period when certain features (e.g Sticky Keys) are activated.


The three items in this section are Display, Zoom and VoiceOver.

Display has been revised. The settings here are intended for those with vision problems. There are now four checkboxes: Invert colors; Use grayscale; Differentiate without Color; Increase contrast (new); and Reduce Transparency. The "Invert" feature (previously called, "White on Black") may also be activated using the key combination of Control + Option + Command + 8. The same key combination turns it off.


Below the checkboxes are two sliders: Display Contrast (Normal to Maximum); and Cursor Size (Normal to Large). The largest cursor is about 1" from end to end. Near the bottom of the panel is a button marked Open Display Preferences.

Zoom provides several ways to control the way zoom may be used. At the top is a checkbox (off by default on my computer) allowing a series of key commands to be used:

Option + Command + 8 zooms in and out;
Option + Command + = zooms in;
Option + Command + - zooms out;
Option + Command + \ toggles smooth images (when off, jagged edges appear).

There is a further option of "Toggle keyboard focus following . . .". On my MacBook Pro this was marked as Unassigned and the key command space was greyed out. This may be added using the Shortcuts pane in System Preferences > Keyboard.

Below the key command options is a checkbox to allow the scroll gesture (e.g. using 2 fingers on a trackpad) to be used with a key to zoom in and out smoothly. Before Mountain Lion (OS X10.8), this had been in the Trackpad preferences. The default key that this works with is Control, but Option and Command are also available as before.


Two other checkboxes below are to turn on Smooth images (wise when zooming); and "Zoom follows the keyboard focus". A button below these checkboxes allows options for the Zoom style. This is allows either a full screen zoom or "Picture-in-Picture" when a panel displays the section of screen zoomed, with the surrounding part not zoomed.


Below these controls is a button marked, More Options which opens a panel with controls for zoom magnification and how the screen behaves during zoom. This panel differs depending on whether Fullscreen or Picture-in-Picture are used as the zoom method.

Additional Zoom Options

VoiceOver provides spoken input for those who need assistance with sound commands. The panel has a simpler text description of the purpose of VoiceOver: "Provides spoken and brailled (sic) control of the computer through the use if the keyboard."

There is a single checkbox: Enable VoiceOver. This may also be turned on using the Command + F5 keys. When either is used, a panel appears and a voice reads out information. There is access to a series of VoiceOver training screens, with a spoken commentary. The screens are made available either through a "Learn More" button on the screen, or by pressing the Space Bar.

Near the bottom of the VoiceOver preference screen are two buttons: Open VoiceOver Training; and Open VoiceOver Utility. The training application reveals the same large screen seen with "Learn VoiceOver" in the panel (above). The system voice reads out the training pages and talks the user through the operations.

The voice was a little fast for my liking (certainly too fast for a non-native speaker), so I adjusted the speed down from Normal in the Text to Speech panel of Dictation & Speech preferences. Even so, it might take a couple of runs through to grasp the full idea.

VoiceOver Utility

The other button opens the VoiceOver Utility panel (similar to System Preferences in appearance) with 10 separate functions, each with their own fine-tuning sections.

These allow VoiceOver to be set up for a user's specific needs and includes settings for any Braille display attached. The same 10 settings are available as before: General, Verbosity, Speech, Navigation, Web, Sound, Visuals, Commanders, Braille and Activities. There are a considerable number of options available within the settings, allowing a high degree of tuning for those who need assistance.


This section includes the new feature, Descriptions. There are two options aimed at those with hearing difficulties:

Descriptions has a brief text explaining the purpose of the setting panel and a single checkbox marked, Play video descriptions when available. This makes available a feature, such as used in some video output, which provides a spoken commentary with video. This is not widely available currently, although some output on sources such as the BBC iPlayer may incorporate such commentary.

Captions was a new option with Mavericks. It is intended for setting up Closed Captions and Subtitles when these are available. The panel is in two parts: a style panel and a checkbox below for turning on Closed Captioning and Subtitles for Deaf and Hard of Hearing (SDH) when available.


When the panel is opened there are three styles of subtitling: Default, Classic and Large Text. Highlighting one of these displays the style in a window above. There are animated clouds behind the text.

It is easy to add (or remove) a style by pressing a + (or -) below the list of styles. Adding a style opens a panel that displays 16 different settings for text fonts, colours and sizes.



Hearing is a new section that has a single option, Audio. The other option in the earlier (Mavericks) version of the Accessibility panel, Captions, is now included in the new Media section, above.

Audio has two basic features (as before): two checkboxes marked

  • "Flash the screen when an alert appears"; and
  • "Play stereo audio as mono."

Between the two is a button to allow a test of the feature. Another button at the bottom of the panel is marked Open Sound Preferences, with the text, "System volume can be adjusted in Sound preferences."


The section named, Interacting, has been available since OS X 10.8, Mountain Lion. In Mavericks a new option of Switch Control was added. In Yosemite Speakable Items has been removed and the preferences are now: Keyboard, Mouse & Trackpad, Switch Control and Dictation.

Keyboard again appears unchanged. With this the keyboard may be adjusted so that those with certain difficulties can type with a little less difficulty. There are two checkboxes in this panel: Enable Sticky Keys; and Enable Slow Keys. If a person is restricted to using a computer with one finger only, even typing a capital letter is a problem. With "Sticky Keys" and "Slow Keys", the Keyboard panel provides some solutions to those with limb-movement problems.


With Sticky keys the last-selected modifier key -- those used in combinations, like Command or Control -- remains active. When turned on (or as a modifier key is pressed), the computer makes a sound. Another sound is made when the feature is turned off. Pressing the key a second time, highlights it (with an optional sound), and pressing a third time cancels the key.

A button marked Options reveals a panel that allows some fine tuning: checking a box allows this feature to be active (or switched off) by pressing the shift key five times. A checkbox below this marked "Beep when a modifier key is set" is slightly misleading: the sound is more like a mechanical "clunk". The placement of the icon that appears may be selected with options for top, bottom, left or right of the screen. [If this option is selected in that panel, sticky keys will activate even when the option on the main pane is unchecked.]

Slow Keys adds a delay for those who have difficulties with initial or repeated keystrokes. Rather than simply tapping a modifier (or other) key as in touch typing, the key remains active and a second Key (or more) may be pressed. As an example I pressed Command then Shift, and then 3 to take a screen shot using one finger only. There is a short mechanical sound when the key is pressed and another when it appears on the screen.

A Slow Keys Option button reveals a slider allowing the acceptance delay to be adjusted, so those with disabilities that make typing very slow can be accommodated. I found that moving the slider more than about 25% along produced a delay so significant I was not sure the keys were being recognised. This was the same in earlier versions of OS X. This may need some careful setting up if it is to be used successfully.

To access more features, there is a button here that opens the Keyboard preferences where full keyboard access and key repeat delays can be set or turned off.

Mouse & Trackpad displays a panel that is in two parts, separated by a thin line. At the top is a checkbox for Mouse Keys. When this is active, the cursor can be controlled using the number pad on the keyboard.

On a notebook computer where there is no number pad, 7, 8 and 9 control upward (and diagonal) movement; U and O control left and right movement; J, K and L control downward (and diagonal down) movement. However, when these keys are used, the normal typing functions of the keyboard are not accessible.


As it is not convenient to keep turning this options on and off to resume typing, an option panel allows a checkbox to be used to toggle the feature On and Off by pressing the Option key five times. Also in the Options panel is a checkbox marked, "Ignore built-in trackpad when Mouse Keys is on." There are two sliders below the checkboxes for Initial Delay (Short - Long) and Maximum Speed (Slow - Fast).

A further useful checkbox in the main panel is the ability to Ignore the built-in trackpad when this feature is on. Two buttons at the bottom of the panel give access to Trackpad Options (scrolling speed, scrolling and dragging), and Mouse Options (Scrolling Speed).

Switch Control was new with Mavericks. It is a highly tunable feature that allows connected devices to be set up with specific controls or options for use by physically challenged users. The panel explains that with this, the computer may be controlled by one or more switches, such as mouse, keyboard, gamepad buttons, or dedicated services.

There is a Knowledge base document - HD6027 for Mavericks, which has an explanation of how these features may be used. There are now three sections to the panel: General, Switches and Navigation:


  • General is a simple panel with two checkboxes: Enable Switch Control; and Hide panel after inactivity, which has a box for entering a time (default 15 secs). A button marked Open Panel Editor reveals a panel that enables a new device or switch to be programmed into the system and operate with specific applications. Using this, a developer may add functions to any of the devices or add new devices to accessibility control. Care needs to be taken when attempting to use such features.

    When Switch Control is made active, a panel appears on the screen with a number of controls available: Keyboard, Pointer, App, Dock, Menubar, System, Custom and Location. Pressing any one of them allows a user to change the behaviour of these input methods. See the Knowledge base document - HD6027 for more information.

    The voice and the motion were too fast initially, but this can be adjusted using a Timing button in the Switches section (below).

  • Switches are the commands that a user would can use to operate Switch Control. The default is a Space Input, which scans between the controls automatically when Switch Control is enabled (a checkbox allows autoscanning to be resumed). A user may reassign the switch or add others using controls beneath the panel. There are also options marked "Required" and "Optional". With device scanning the user may also select Timing using a button at the bottom of this panel.

  • Navigation displays a series of buttons that allow fine-tuning of the way scanning operates apparently when navigating the screen. Operation controls available are:

    • While navigating
    • Restart position
    • Auto scanning after select
    • When pointer reaches edge (previously referred to "mouse")
    • Switch Control cursor size
    • Pointer precision
    • Loops


This panel provides a number of ways in which devices can be tuned so that they provide better input for users. Apple has provided some documentation in the that allows users and developers to make use of these controls. This text will be updated if more documentation becomes available. There are also a couple of useful articles from other sources, directly involved with providing assistance to disabled people.

Useful Sources:

Dictation is designed to allow control of the computer using voice and, although not clear in this panel, needs to be used with Dictation & Speech preferences. Since this first appeared, I have had limited success with this, particularly when using older applications.

There is now a single (and much simplified) panel here with just one button: Dictation Commands. This opens a panel on which there is a list of commands that are available to the user in 5 sections: Selection, Navigation, Editing, Formatting, and System.

Alternative language sets are available. As I have downloaded enhanced dictation sets for UK and Thai, commands for these are also available in the Dictation Commands panel. Access to the different language sets is via a button near the top of the page.


A checkbox underneath the list is marked Enable advanced commands. Using this adds a number of commands and also adds two more sections: Application and Document. A further section marked User is added at the top of the list if the box is checked and this allows user specific texts (undefined commands) to be added. Parameters for the user commands include, When I say. . ."; While in (any application, or a specific one); Perform (a button allows certain actions to be selected).


See also:

  • Apple information on Braille display use

  • Information on Accessibility from Apple

    Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand where he is also Assistant Dean. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs. He is now continuing that in the Bangkok Post supplement, Life.



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All content copyright © G. K. Rogers 2014