What Is Font Proofing?
Font proofing is the process of evaluating a typeface in development by rendering it in structured test documents, called proofs. A proof puts the font through realistic and deliberately stressful situations: running text, size waterfalls, full character grids, kerning strings. The point is to surface drawing, spacing, and engineering problems before the font ships.
The name comes from printing, where a “proof” was the trial impression you checked before committing to a full press run. Type designers kept the term and the habit. A typeface gets judged by reading it, at real sizes, in real settings, and ideally on paper.
Why proofing matters
A font editor shows you one glyph at a very large size. Almost every problem that matters shows up somewhere else:
- Spacing problems appear in running text. A lowercase “n” can look perfect alone and still create holes in a paragraph.
- Kerning problems appear in specific letter pairs (“Ta”, “AV”, “f)”) that you only catch by rendering those pairs systematically.
- Size problems appear when type is set small. A hairline that looks elegant at 200pt can disappear at 9pt.
- Texture problems (uneven color, rhythm, or weight across a paragraph) are only visible in blocks of body text.
- Coverage problems (missing diacritics, broken OpenType features, wrong numerals) only show up when you systematically render everything the font claims to support.
Proofing is how type designers catch all of this. Most designers proof continuously throughout a project: draw, proof, adjust, repeat.
The standard types of proof
Different problems require different documents. These are the proof types used across the industry:
| Proof type | What it shows | What it catches |
|---|---|---|
| Basic text / paragraph | Running copy at body sizes | Texture, rhythm, spacing, readability |
| Waterfall | The same text repeated at increasing point sizes (e.g. 8–96pt) | Size-specific problems: weak hairlines, clogging joins, spacing that only works at one size |
| Glyph grid / character set | Every glyph in the font, with metric lines | Missing glyphs, inconsistent heights, alignment errors, drawing inconsistencies |
| Spacing strings | Control-character patterns like “HHaHH HHbHH” or “nnonno” | Sidebearing errors, glyphs that are too tight or too loose |
| Kerning strings | Known problem pairs (“AV”, “Ta”, “f?”, quotes and punctuation) | Missing or excessive kerning |
| Style comparison | The same text in multiple weights or styles side by side | Inconsistencies across a family; whether the roman and italic agree |
| Diacritics | Accented characters per language (Czech, Polish, Vietnamese, …) | Misplaced or colliding accents, missing language support |
| Pangrams & word lists | Sentences using every letter (“Sphinx of black quartz…”) | Quick whole-alphabet sanity checks in context |
A complete proof document usually combines several of these into one PDF that can be printed, reviewed, and marked up.
How proofing fits the workflow
A typical loop while a typeface is in development:
- Draw or adjust glyphs in a font editor (Glyphs, RoboFont, FontLab)
- Generate or refresh a proof document
- Review on screen and in print. Paper shows weight and spacing problems that screens hide.
- Mark up problems: circle weak joins, note spacing fixes, flag kerning pairs
- Go back to the editor and fix them
- Repeat until the marked-up proof comes back clean
Historically, step 2 was the friction. Designers exported font files, installed them, opened InDesign templates, relinked fonts, and re-exported PDFs, and they did all of it for every single iteration. Many wrote their own Python scripts (DrawBot is popular) just to automate proof generation.
How Font Proof handles it
Font Proof is a Mac app built specifically for this loop. It connects directly to Glyphs.app: when you save your Glyphs file, the proof PDF updates within seconds, with nothing to export, install, or refresh. The document is a real PDF the entire time, so what you see on screen is exactly what prints.
It ships with the standard proof types built in (waterfalls, glyph grids with metric lines, columns and rows, style comparisons, and basic text), plus templates for spacing tests, kerning strings, pangrams, and diacritics in 26 languages. You can mark up a frozen snapshot of the proof directly in the app, and the notes live inside the proof file.
Font Proof costs $100 once (no subscription), has a 14-day free trial, and requires macOS 14 (Sonoma) or later. See the full feature list or read the docs.
When you’re ready to do a final pass before release, work through the font proofing checklist.
Frequently asked questions
What is a font proof?
A font proof is a test document, usually a PDF, that renders a typeface in structured layouts (running text, size waterfalls, character grids, kerning strings) so a type designer can evaluate spacing, kerning, drawing consistency, and language coverage before the font is released.
Why do type designers print proofs?
Paper shows problems that screens hide. Screen rendering applies anti-aliasing and hinting that can mask weight, contrast, and spacing issues, and reading on paper engages different judgment than scrolling. Most experienced designers review proofs both on screen and on paper.
What software is used for font proofing?
Common approaches are custom Python scripts (often with DrawBot), InDesign templates with manually relinked fonts, web-based specimen tools, and dedicated apps. Font Proof is a dedicated macOS proofing app with live Glyphs.app integration, so the proof updates automatically every time you save.
How often should you proof a typeface?
Continuously. Proofing works best as a habit that runs through the whole project: draw, proof, adjust, repeat. The cheaper it is to generate a proof, the more often you’ll actually do it.
What text should you use in a proof?
A mix: pangrams and spacing strings for systematic coverage, real running copy for texture and rhythm, kerning strings for known problem pairs, and language-specific texts for diacritics. Nonsense-word generators and standard texts both have a place, since you want to cover controlled patterns and realistic reading.