Bad Eyesight - Thunderbird

This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

• There are a few themes designed for high contrast at the Mozilla Add-ons web site.

• The Theme font & size changer add-on works with both Firefox and Thunderbird. It changes the fonts/font sizes in menus, toolbars etc. but not within a message.

• You can change the font/font size in messages using Tools -> Options -> Display -> Fonts -> Advanced. Make certain you also set "minimum font size" and consider unchecking "allow messages to use other fonts". If you don't want to change the font size you could set View -> Message Body As > Simple HTML. That removes some of the display formatting within the message such as font sizes and colors. It may not look as nice, but you can read the small print again.

• The QuoteAndComposeManager add-on lets you specify a fixed-size font in the headers for HTML mail .

• The MailTweak add-on has a Tree font tweak that sets the font size in the folder pane, thread pane and address book. You will need to install the add-on compatibility reporter add-on (to disable version checking) in order to install it as doesn't support versions later than 3.*

• Pane and menu fonts has CSS snippets you can add to a optional UserChrome.css file to change the font, font size, and other attributes of fonts. Personalize your Thunderbird by changing it’s chrome also has some useful CSS snippets. If you don't want to learn how to use a CSS snippet you could try using a already customized CSS style from UserStyles.org using the Stylish for Thunderbird add-on. For example, TwisterMc's "Make TB labels stand out" style tries to make it easier to see tagged messages and the list box alternating row bg colors style configures alternating rows to use a different background color in list boxes/folder listings.

• You can use "Control +" (using the auxiliary keypad), "Control Shift +" (using the main keyboard) or View -> Zoom when viewing messages to increase the text size but when writing a message there is no Zoom option and the shortcut doesn't work. That setting will apply to any message you read, but its not sticky, when you exit and restart Thunderbird you'll have to do it again. That is why its typically easier to use one of the add-ons or CSS snippets to permanently change how something looks. If you can't zoom try temporarily disabling all add-ons using Safe mode (not to be confused with Windows safe mode) to see if an add-on is the culprit.

• The Montezooma add-on adds zooming capabilities to the message window. The ImageZoom add-on lets you zoom images.

• The Compose for Thunderbird add-on is an experimental add-on that replaces the built-in editor, based on the existing CKEditor WYSIWYG Text and HTML editor. Eventually Mozilla Messaging will add its features to Thunderbird and remove the add-on from the web site. It is currently nowhere near full functionality and has many bugs but later on you might want to investigate if it makes things easier.

Sending Messages

There isn't much you can do to make a plain text message more easily readable. However, you can change the font and font size and bold the text in a HTML message to make it easier for the recipient to read it. The easiest way to do this is to create a message template and use it to create a new message whenever you send a message to somebody with poor eyesight. If you have any sort of organized data consider putting it in a table.

Use fixed font sizes for sending your messages with caution. In general, you can assume that the recipient will have made adjustment to his or her settings optimum for their needs, thus you may inadvertently override such settings.

Thunderbird 5.0 and later

Thunderbird 5.0 has Direct2D font rendering enabled by default on Windows platforms which support it (so does Firefox 4.0+ and SeaMonkey 2.1+). This is in addition to the ClearType handling described below. If the fonts remain difficult to read after adjusting the ClearType settings, go into Tools → Options → Advanced → General and click on Config Editor. Switch the gfx.direct2d.disabled setting to "true" by double-clicking on it to disable the D2D feature. You need to restart Thunderbird to see its effect.

If you are using the High Contrast desktop themes on Windows 7 or Vista, hard-wired colors and gradients introduced during the redesign of the "aero" default theme may make reading the menu bar and the toolbar buttons difficult (screendumps). There is a userChrome.css workaround available to increase visibility of the menu and button texts (CSS code, screendump).

Other solutions

There is a limit to what you can do within Thunderbird. It might be better to try to use some of the accessibility features of your operating system instead of tweaking each application.

• If you're using Windows run the accessibility wizard at Start -> Programs -> Accessories -> Accessibility. If that doesn't help there is always Start -> Programs -> Accessories -> Accessibility -> Magnifier

• The default and many other desktop themes on Windows 7 and Vista employ a "glass" effect with transparency, which may make it hard to recognize text and shapes. Chose the Windows Classic or one of the High Contrast themes by selecting the Appearance tab in the Display Properties control panel, and then Color Scheme. On Windows 7, right-click on the desktop and select Personalize from the context menu.

• If you have a LCD monitor, use the cleartype tuner powertoy to tune the the text to your eyesight. On Windows 7, right-click on the Desktop and select Personalize from the context menu, then select Display and choose the "Adjust ClearType text" category. If you prefer unsmoothed (crisp) fonts, uncheck "Turn on ClearType" to avoid font smoothing.

• Dragon Naturally Speaking is speech recognition software, but it also has a text-to-speech option. You might buy something like that to speak what you are reading.

See Also

• Use my colors
• Pane and menu fonts
• White on black - Thunderbird
• Assistive technology compatibility
• Category:Visual_customizations_(Thunderbird) has several articles about using CSS to customize the user interface.

Forum Links

• Dark theme with high contrast for people with visual problems
• Dim display on some or many characters
• Thunderbird is not kind to visually impaired users

External Links

• Macros's accessibility blog discusses Firefox and Thunderbird.
• David Ascher blog entry about low vision theme
• Thunderbird doesn't maintain named composition font thread
• AccessFirefox web site has tools and resources for Firefox users with disabilities. While Firefox-centric if you find a useful theme in the list of Firefox Accessibility themes that might help you find the equivalent for Thunderbird.

Bug reports

• Text zoom in composer
• No text zoom in composer