AAT Font Quality Specification
METRICS
Fonts acquire their printing metrics (positioning along the line) from
their placement on screen. When proofing waterfalls, metrics should be
set for their best possible display for the device being used for proofing.
When editing glyphs on-screen (72dpi), Fractional Character Widths should
be disabled (integer spacing on) allowing for maximum on-screen legibility.
When proofing printer output, the text should be printed with Fractional
Character Widths enabled (integer spacing off), allowing the printed glyphs
to space as well as possible.
Positioning verification
Summary of tasks:
Optical test suites would be printed on high- and low-resolution devices,
so instructions matter, but outline integrity must be assumed.
Examples:
- Spacing (6-18, 20, 22, 24, 28 point).
- every uppercase glyph between H and O.
- every lowercase glyph between n and o.
- every figure and math glyph between 0 and 1.
- symbols and punctuation in one of the above as appropriate.
(AAT) Optical test suites for AAT check whether appearance-specific
tables like 'opbd', 'trak', and 'just' give the desired results: the visual
effects of Line Layout table values.
- extrapolate to AAT (e.g., every small cap between (small cap) H and
O).
- Tracking: a set of test phrases at 1200 dpi, waterfalled through many
sizes, then the whole thing waterfalled through multiple tracking settings.
- Justification: test phrases at 1200 dpi, at a fixed width, waterfalled
through many sizes.
- Kerning: every kern pair between H O n o as appropriate; this may have
some overlap with collision avoidance tests.
- Optical bounds: all glyphs vertically between H O n o at 1200 dpi,
if vertical optical bounds are used. If the designer is using the control
point format of 'opbd', s/he must also do those proofs at 300 and 72 dpi
(since control points can be instructed)
- Baseline: multiple scripts at 1200 dpi. Standardized test fonts with
appropriate baselines to refer to are needed.
Technical details:
Proof at 1200+ dpi for the ideal case.
(AAT) AAT should mean that the designer does not have to worry about
lower- resolution cases (except for instructed control points).
Arleigh Movitz
The Apple Fonts Group
|
