MacOS – How to increase the font sizes without decreasing the resolution

There is a feature that's currently experimental called HiDPI that may do what you want. Like the retina displays on the iPhone and iPad, HiDPI mode creates a "logical" resolution that's half the current resolution on your display but uses all the physical pixels to keep the image sharp. This results in all the user interface elements appearing much larger, but with no lack in clarity. For example, if you're outputting to a 1080p TV with a resolution of 1920x1080, the HiDPI resolution would be 960x540, and all the elements on the screen would be the same size as if you were outputting that physical resolution.

To enable HiDPI mode in Mac OS X Lion:

1. Download the "Graphics Tools for Xcode" download from Apple. This download requires you to enter an Apple ID, which you most likely have and can get for free.

2. Mount the DMG

3. Open the "Quartz Debug" app

4. In the menu bar, select "Window", then "UI Resolution"

   

5. Check "Enable HiDPI display modes"

6. You'll be prompted to log out and log back in. If multiple accounts are logged in, they must all log out for the change to work.

7. Once you log back in, go to System Preferences, then Displays. You will see the new HiDPI modes there.

   

8. For your 1080p TV, select "960x540 (HiDPI)"

P.S. If you're curious what HiDPI mode looks like, the screenshots I've taken are both in HiDPI. Click on them to see them full sized.

Above all, text must be legible. If users can’t read the words in your app, it doesn’t matter how beautiful the typography is. When you adopt Dynamic Type in your app, you get:

• Automatic adjustments to letter spacing and line height for every font size
• The ability to specify different text styles for semantically distinct blocks of text, such as Body, Footnote, or Headline
• Text that responds appropriately to changes the user makes to text-size settings (including accessibility text sizes)

Make sure all styles of a custom font are legible at different sizes. One way to do this is to emulate some of the ways iOS displays font styles at different text sizes. For example:

• Text should never be smaller than 11 points, even when the user chooses the extra-small text size. For comparison, the body style uses a font size of 17 points at the large size, which is the default text-size setting.
• In general, font size and leading values differ by one point per text-size setting. Exceptions to this are the two caption styles, which use the same font size, leading, and tracking at the extra-small, small, and medium settings.
• At the smallest three text sizes, tracking values are relatively large; at the largest three text sizes, tracking values are relatively tight.
• The headline and body styles use the same font size. To distinguish it from the body style, the headline style uses a heavier weight.
• Text in a navigation controller uses the same font size that body style text uses for the large setting (specifically, 17 points).
• Text always uses either regular or medium weight; it doesn’t use light or bold.

iOS Human Interface Guidelines: Color and Typography