# stixfonts

OpenType Unicode fonts for Scientific, Technical, and Mathematical texts

See https://www.stixfonts.org/ for background on the the STIX Fonts project.

The Scientific and Technical Information eXchange (STIX) fonts are intended to meet the demanding needs of authors, publishers, printers, and others in the scientific, medical, and technical fields. They combine a comprehensive Unicode-based collection of mathematical symbols and alphabets with a set of text faces suitable for professional publishing. They are available royalty-free under the SIL Open Font License, Version 1.1.

Version 2 of the STIX fonts, now known as “STIX Two”, is a thorough revision of version 1 undertaken by the renowned type house Tiro Typeworks. The STIX Two fonts consist of four text fonts (Regular, Italic, Bold, and Bold Italic) and one Math font. Together, they provide a uniform set of fonts that can be used throughout the production process, whether that be a traditional print-only process, an entirely electronic one, or a combination of the two.

The STIX project began through the joint efforts of the American Mathematical Society (AMS), the American Institute of Physics (AIP), the American Physical Society (APS), the American Chemical Society (ACS), the Institute of Electrical and Electronic Engineers (IEEE), and Elsevier. These companies are collectively known as the STI Pub companies.

### A Fresh Take on Times Roman

The original version of STIX was based on Times Roman, which has now been updated for the digital age.

As is well known, Times Roman was originally intended for printing the London Times. What is not generally appreciated is that the production quality of the Times was atypically high: It was printed on unusually high-quality paper on presses that operated more slowly than most newspaper presses. This allowed for the design of a typeface that could exploit this level of care: serifs could be much finer and counters (enclosed areas such as that in the lowercase e) could be much smaller than in other newspaper typefaces. These features of the font have not always fared well in less exacting environments. At the same time, a notable quirk of the Times Roman family is that the bold font is, in many respects, strikingly dissimilar to the roman font.

Tiro Typeworks explain their approach to updating the Times Roman basis of STIX as follows:

“Our principal goal in approaching STIX Two was to address several
inherent deficiencies in the Times New Roman model as well as expand
the typographic features. This process necessarily involved
diverging somewhat from Times as familiar to people who have only
known the common digital versions, while simultaneously restoring to
that typeface aspects of the size-appropriate design characteristics
that made it so successful in newspaper, book, and journal
publishing in it’s metal type incarnation. The essential
‘Times-ness’ remains, but are with greater harmonisation of style
across the family.

“Most digital versions of Times have been based on an optical size
model that appears too light and fine when scaled down to typical
text sizes. In the design of STIX Two, we went back to specimens of
size-specific designs from the metal era, and adapted proportions,
weights, and spacing of the 10pt and 12pt designs. The oft-noted
mismatch between the style of different weights of Times has been
resolved with a new bold design that matches the construction of the
regular weight.”

### Font implementation decisions

• The STIX fonts do not contain fixed-width or sans serif text faces.
• The sans serif, fraktur, script, etc., alphabets in Plane 1 (U+1D400-U+1D4FF) are intended to be used only as technical symbols.
• These fonts are designed to support left-to-right typesetting in Latin-based scripts, with additional support for Greek and Cyrillic text. Extensions to support other writing directions have been considered, but are currently deemed to be outside the scope of the STIX project.

### Note to TeX users

These fonts have been tested with both and lua with good results. For best results, users will want to use version 0.99999 or later of , which ships with Live 2018. This version fixes a number of bugs that were present in earlier versions. Our thanks go out to Jonathan Kew and Khaled Hosny for their generous help in identifying and fixing these bugs. users should also make sure they have the latest version of the amsmath package.

## Summary of OpenType Features and Scripts

Further details these features can be found in the code charts.

The four text fonts implement the following OpenType script tags:

Regular   Bold      Italic    BoldItalic

DFLT      DFLT      DFLT      DFLT          Default
cyrl      cyrl      cyrl      cyrl          Cyrillic
cyrl.MKD  cyrl.MKD      Cyrillic/Macedonian
cyrl.SRB  cyrl.SRB      Cyrillic/Serbian
grek      grek      grek      grek          Greek
latn      latn      latn      latn          Latin
latn.ROM  latn.ROM  latn.ROM  latn.ROM      Latin/Romanian
latn.TRK  latn.TRK  latn.TRK  latn.TRK      Latin/Turkish

and the following features

c2sc    Small Capitals from Capitals
case    Case-Sensitive Forms
ccmp    Glyph Composition/Decomposition
dnom    Denominators
frac    Fractions
kern    Kerning
liga    Standard Ligatures -- latn only
locl    Localized Forms    -- latn.ROM and Italic/BoldItalic cyrl.MKD only
numr    Numerators
onum    Oldstyle Figures
pnum    Proportional Figures
smcp    Small Capitals
subs    Subscript
sups    Superscript

All four text fonts also support the following Character Variants:

cv01    U+019B Lambda with horizontal, not slanted stroke -- latn only
cv02    U+0264 Rams horn with serifs -- latn only
cv03    U+2423 OPEN BOX curved instead of straight

In addition, the Italic and BoldItalic faces support the following Stylistic Variants:

ss01    Replace two-story g by hooked g      -- Italic/BoldItalic only
ss02    Upright parens, brackets, and braces -- Italic/BoldItalic only

STIX Two Math implements the following font features:

ccmp    Glyph Composition/Decomposition
dtls    Dotless forms of i and j
flac    Flattened accents
ssty    Math Script style alternates

and the following Character Variant (note the different meaning compared to the text fonts):

cv03    Replace U2205 EMPTY SET by an oblate form

and the following Stylistic Sets (again, note that ss01 and ss02 have different meanings compared to the text fonts):

ss01    Stylistic Set 1 -- Math chancery to roundhand (\mathcal -> \mathscr)
ss02    Stylistic Set 2 -- Alternate italic forms: g, u, v, w, z
ss03    Stylistic Set 3 -- Horizontal crossbar variants
ss04    Stylistic Set 4 -- Minute, second and primes to long variants
ss05    Stylistic Set 5 -- Short arrow variants
ss06    Stylistic Set 6 -- Short/narrow variants
ss07    Stylistic Set 7 -- Alternate math symbols (product, summation, etc)
ss08    Stylistic Set 8 -- Upright integral variants; XITS compatible
ss09    Stylistic Set 9 -- Vertical slash variants; XITS compatible
ss10    Stylistic Set 10 -- Diagonal greater/lesser combination variants
ss11    Stylistic Set 11 -- Long slash not-equal combination variants
ss12    Stylistic Set 12 -- Low contrast (sans-like) variants
ss13    Stylistic Set 13 -- Horizontally flipped sine wave glyph
ss14    Stylistic Set 14 -- Tall variants
ss15    Stylistic Set 15 -- Slab serif symbol variants
ss16    Stylistic Set 16 -- Circled operator variants
ss20    Stylistic Set 20 -- Miscellaneous variants