Typotheque

OpenType features

Typotheque fonts currently use the following OpenType features:
ORDN (Ordinals)
Replaces default alphabetic glyphs with the corresponding ordinal forms for use after figures. Example: The user applies this feature to turn 2o into 2º (abbreviation for secundo).
Ordinals OpenType feature

FRAC (Fractions)
Replaces figures separated by a slash with ‘common’ (diagonal) fractions or creates a new fraction. Example: The user enters 2/3 in a recipe and gets the twothirds fraction.
Fractions OpenType feature

DNOM (Denominators)
Replaces selected figures which follow a slash with denominator figures. In the string 11/17 selected by the user, the application turns the 17 into denominators when the user applies the fraction feature. It works in combination with FRAC feature.
NUMR (Numerators)
Replaces selected figures which precede a slash with numerator figures, and replaces the typographic slash with the fraction slash. Example: In the string 11/17 selected by the user, the application turns the 11 into numerators, and the slash into a fraction slash when the user applies the fraction feature. It works in combination with FRAC feature.
LIGA (Standard Ligatures)
Replaces a sequence of glyphs with a single glyph which is preferred usage for typographic purposes. This feature covers the ligatures which the designer/manufacturer judges should be used in normal conditions. Example: The glyph for ffl replaces the sequence of glyphs f f l.
Standard ligatures OpenType feature

DLIG (Discretionary Ligatures)
Replaces a sequence of glyphs with a single glyph which is preferred usage for typographic purposes. This feature covers those ligatures which may be used for special effect, at the user's preference. Example: The glyph for ct replaces the sequence of glyphs c t.
Discretionary ligatures OpenType feature

CALT (Contextual Alternates)
In specified situations, replaces default glyphs with alternate forms which provide better joining behavior. Used in script typefaces which are designed to have some or all of their glyphs join. Example: In Fedra Display, space+T+H+E+space is replaced by a logo-like glyph THE.
Contextual alternates OpenType feature

SUPS (Superscript)
The SUPS feature may replace a default glyph with a subscript glyph, or it may combine a glyph substitution with positioning adjustments for proper placement.
Superiors OpenType Features

SINF (Scientific Inferiors)
Replaces lining or oldstyle figures with inferior figures (smaller glyphs which sit lower than the standard baseline, primarily for chemical or mathematical notation). May also replace lowercase characters with alphabetic inferiors. Example: The application can use this feature to automatically access the inferior figures (which are more legible than scaled figures).
Subscript OpenType Features

AALT (Access All Alternates)
This feature makes all variations of a selected character accessible. Example: A user inputs the 'A', and is presented with a choice of the four standard capital forms, the eight swash capital forms, the initial capital form and the small capital form.
LOCL (Localized Forms)
Many scripts used to write multiple languages over wide geographical areas have developed localised variant forms of specific letters, which are used by individual literary communities. For example, a number of letters in the Bulgarian and Serbian alphabets have forms distinct from their Russian counterparts and from each other. In some cases the localised form differs only subtly from the script 'norm', while in others the forms are radically distinct. This feature enables localised forms of glyphs to be substituted for default forms. Example: The user applies this feature to text to enable localised Bulgarian or Serbian forms of Cyrillic letters.
Localised forms OpenType feature

ONUM (Oldstyle Figures)
This feature changes selected figures from the default style to oldstyle form. Example: The user invokes this feature to get oldstyle figures, which fit better into the flow of normal upper-and-lowercase text setting. Various characters designed to be used with figures may also have oldstyle versions.
Old style numerals OpenType feature

LNUM (Lining Figures)
This feature changes selected figures from default to the lining form. Example: The user invokes this feature in order to get lining figures, which fit better with all-capital text setting. Various characters designed to be used with figures may also be covered by this feature. In cases where lining figures are the default form, this feature would undo previous substitutions.
Lining numerals OpenType feature

PNUM (Proportional Figures)
Replaces figure glyphs set on uniform (tabular) widths with corresponding glyphs set on glyph-specific (proportional) widths. Tabular widths will generally be the default, but this cannot be safely assumed. Of course this feature would not be present in monospaced designs. Example: The user may apply this feature to get even spacing for lining figures used as dates in an all-capitals headline.
TNUM (Tabular Figures)
Replaces figure glyphs set on proportional widths with corresponding glyphs set on uniform (tabular) widths. Tabular widths will generally be the default, but this cannot always be assumed. Of course this feature would not be present in monospaced designs. Example: The user may apply this feature to get oldstyle figures to align vertically in a column.
Tabular numerals OpenType Feature

SALT (Stylistic Alternates)
Many fonts contain alternate glyph designs for a purely aesthetic effect; these don't always fit into a clear category like swash or historical. As in the case of swash glyphs, there may be more than one alternate form. This feature replaces the default forms with the stylistic alternates. Example: The user applies this feature to Fedra Sans to get the alternate form of g.
Stylistic Alternates OpenType Features

ZERO (Slashed Zero)
Some fonts contain both a default form of zero, and an alternative form which uses a diagonal slash through the counter. Especially in condensed designs, it can be difficult to distinguish between 0 and O (zero and capital O), in any situation where capitals and lining figures may be arbitrarily mixed. This feature allows the user to change from the default 0 to a slashed form. Example: When setting labels, the user applies this feature to get the slashed 0.
Slashed zero

These descriptions are used by permission. For more, see full OpenType Tag definition at
http://partners.adobe.com/public/developer/opentype/index_tag3.html
© Adobe Systems Inc. & Microsoft Inc.
Special thanks to Thomas Phinney.