What you need to know about Autohinting

by Rainer Erich Scheichelbauer

6 January 2013 Published on 8 June 2012

The built-in autohinter needs two things: representative stem values and representative alignment zones.

  1. Open your Font Info window and go to the Masters tab.
  2. First you measure the widths of your vertical and horizontal stems and bows and enter them in the fields for Vertical Stems and Horizontal Stems, respectively.
  3. Repeat this step for every master you have in your font. Make sure the number and order of the stem values is compatible throughout all masters, so interpolation can take place.
  4. Now, make sure your vertical metrics are set right: ascender, cap height, x-height, descender. The values entered here should ignore overshoots. When in doubt, pick the value close to the baseline. If you have small caps, you may want to add the custom parameter ‘smallCapHeight’ and enter their height as parameter value.
  5. Now hit the grey circled arrow next to the Alignment Zones field. Glyphs will try and guess the values based on your vertical metrics and the actual overshoots in your font master.
  6. Again, repeat these steps for all the masters in your font. Make sure number and ordering of the zones are consistent throughout all the masters.
  7. It’s a good idea to check if Glyphs guessed the zones right. So quickly step through your glyphs and see if there’s an overshoot that misses its zone. If you have the Metrics option activated in the View menu, Glyphs will display alignment zones as beige areas.
  8. When you adapt your zones, keep in mind that no zone should become larger than 25 units. There should also be at least one unit distance between the zones.

That’s it! Not so bad actually. Now export your font with the ‘Autohint all glyphs’ option enabled. You can test your hinting in applications that have their own renderer, like Adobe applications. If you want to test it in TextEdit, you first need to turn off font smoothing in the General options in System Preferences, and in TextEdit, set the font size to 12 points or smaller.

These few steps do pay off. Here’s what Typejockeys’ Henriette looks like in InDesign without hinting:

Same font, same text, same app, but this time with hinting:

Note that the text appears crisper, there is less fuzziness, and the heights of the letters appear more consistent.