AAT Font Quality Specification
(AAT) VARIATIONS CHARACTERISTICS
Due to the much larger potential number of glyphs, and the numerous axes
of variation available to a AAT variant font, proofing becomes a much more
involved job. No longer can a single set of waterfalls showing a family
of fonts at a range of sizes provide the necessary range to confirm to
a designer that no bugs exist in the instructing of a font. With a non-variant
AAT font, the proofing task increases mathematically in direct proportion
to the number of glyphs in the font. In a variations font, the number of
glyphs to be proofed increases geometrically, to the point where it can
become impossible to examine every possible glyph in every combination
of variations in any timespan measured in less than person-years.
Because of this, methods for proofing and error detection must change.
Intelligent spot-checking, and placing greater reliance on having the tools
that create the font do the right thing in the first place without supervision
will be necessary; similar in many ways to an industrial assembly line.
Anticipating and eliminating the causes of problems, rather than a reliance
on catching the problems after the font has been instructed, will be the
guarantee to quality. Because of this, the typographer will have to work
closely with the engineer to perfect the font tools.
At a minimum, it is a good idea to do a complete examination of each
axis extreme, and at the center of the style matrix that are most likely
to be used. In figure 9-1, a sample minimal variations matrix is shown,
an example of a two bidirectional axes (weight and width) font, with a
central position on each axis representing the "normal" setting.
All of the nine instances (positions on the grid) should be examined during
an comprehensive edit.
fig. 9-1 A sample minimal variations matrix.
This is why a variant font will take more effort than a standard font
to proof: instead of the four fonts of a non-variant family to be checked,
there are a minimum of nine. If additional inner-matrix instances are considered
important, than they should be examined as well. In addition, spot checking
of other positions is useful if time and energy allows.
If a third complete axis is added (slant, for example, or variable serifs),
then the number of instances that require examining increases to a minimum
of 27. However, since a "proper" shipping font family might include
4 styles, the effort in producing the family would be four times as much
effort as for a single font. In addition, a family of styles needs to be
coordinated (when stems break, compatible layout tables where possible,
etc.) This coordination comes for free with a variant font, since it only
has one copy of its hinting and layout tables, rather than 4, so while
a variant font is more work than any single font, it may in some ways save
work as compared to a traditional family of fonts, which it can also replace.
At the time of this writing, few complete variations fonts have been
created. This document will be revised as more information becomes available.
Arleigh Movitz
The Apple Fonts Group
