Setting Font in Thunderbird

Thunderbird is a web-based rendering engine. This means that it is slightly different from Microsoft Outlook where Thunderbird uses pixel points instead of size point. This section guides you on how to alter font and its properties in Thunderbird for both send/receive email.

Understanding Email Font

Upto Receiver Decides the Font Size

Unless otherwise specified (as in manually coded), sending email is always written in a relative font manner. Example:

  1. Largest (+4)
  2. Large (+2)
  3. Normal (+0)
  4. Small (-2)
  5. Smallest (-4)

It is always the responsibility of the receiver to intepret the actual size. Example, say the receiver set the font at 22px for normal size, the above scale produces:

  1. Largest = 26px
  2. Large = 24px
  3. Normal = 22px
  4. Small = 20px
  5. Smallest = 18px

Hence, the focus is about setting your “receiving font size” where Thunderbird will use the same settings to render your sending email font size.

HTML-Format Only

These font configurations only make sense if the email is composed in HTML format. Otherwise, the “text-only” format only contains a standard, single font text.

Configure Thunderbird to Compose HTML Email

To ensure Thunderbird always compose HTML-format, you can head to Tools > Account Settings and do the following:

  1. Select Composition & Addressing under your account.
  2. Check Compose messages in HTML format.
  3. Press OK.

This ensures that your sending email are always composed in HTML format.

Configure Thunderbird Send HTML

Changing Actual Font

Once done, head over to Options to start changing the actualy font. Select Display item on the right panel to begin. Then:

  1. Set the default font of your choice.
  2. Set the font size based on pixel, not point. ZORALab recommends 13-18.
  3. Select Advanced.

FOR YOUR INFORMATION: points to pixel conversion

  1. 10pt15px
  2. 12pt18px
  3. 14pt21px

Set basic font

Set Advanced Font and Size by Language Characters

Similar to any other email clients, you need to change your font and size according to language characters (e.g. Chinese characters or Hindu characters). These characters are not supported natively by certain fonts such as Verdana. Similarly, SimSun and YaHei may or may not supports all greek characters. Therefore, you should only alter languages that you use based on a given font.

The one you’re primarily interested in is English, which falls under 2 categories: Latin and Other Writing System. Let’s do them one by one:

  1. Select the Font for to that Other Writing System category.
  2. Change your font type and font size accordingly. To keep things simple, please ensure you set your mininum font size to None.
  3. Un-check Allow messages to use other fonts. Otherwise, your typing can magically turn into another font since it’s based on the fonts from the surrounding texts.
  4. Check Use fixed width font for plain text messages.
  5. Set Outgoing Mail to Unicode (UTF-8).
  6. Set Incoming Mail to Unicode (UTF-8).
  7. Un-check When possible, use the default text encoding in replies.
  8. Select OK when done.
  9. Select Advanced... again.
  10. This time, select the Font for to Latin category.
  11. Repeat Step 2 to Step 8 for Latin category.
  12. Select OK when done.
  13. Repeat Step 10 for other foreign languages that you use.

Change Other Writing Systems Font Change Other Writing Systems Font

Set Composing Options

Once done, we need to configure composing options. By default, there are not much to change here. However, you should check the following:

  1. This time, select Composition from the right tab.
  2. Select Variable Width for font.
  3. Select Medium.
  4. Uncheck Use Paragraph instead of Body Text by default.

That’s all.

Change Composition Font

Test Sending Your Email

With everything is done, you should try composing your email to your alternate account or to your colleague to checkout its typography.

On Thunderbird, you can compose something as such:

Compose test email

Then have the owner verifies the receiver-end email. Example, on Gmail, it looks something as such:

Verify test email