[2 mod] Style: v ν x χ Greek and Latin characters use the same glyph in italic style

[adoa]

Rendered in 21pt Italic

Sample Glyphs:

ν=v x=χ

Description:

Some lowercase Greek and Latin characters use the same glyph in italic style.
This is quite unfortunate for formula typesetting. Especially in physics.
Many sans-serif fonts have this problem. It is the reason most people use serif fonts for formula typesetting, including myself. Since in almost every font, many of the Greek uppercase letters share glyphs with Latin uppercase letters, these Greek uppercase letters are not distinguished from the equivalent Latin uppercase letters in formula typesetting: ABEHKMNOTXZ ...
Thus the ambiguity is usually given by using lowercase Greek and Latin letters. As far as I know, in formula typesetting the lowercase letters are usually used in italic style. So it would be great if at least the italic versions are distinguishable. The only exception I know about, is the Greek υ (U+03C5) which is often hard to distinguish from Latin u (U+0075), so in formula typesetting usually only the latter is used.

In the current ubuntu-font the following characters share the same glyph:
 • the Greek ν (nu) and Latin v, which is awful for semi classical calculations for example
 • the Greek χ (chi) and Latin x, which is a problem if an indicator function is named χ and the variable is x (see also bug 647092)

In most sans-serif fonts these two cases are unambiguous in italic style. So these occur more often than one would think.

UA String:

Mozilla/5.0 (X11; U; Linux x86_64; de; rv:1.9.2.10) Gecko/20100915 Ubuntu/10.04 (lucid) Firefox/3.6.10

[Mark Shuttleworth (sabdfl)]

Given that Ubuntu has its roots in technical work, and precision is one
of our core values, I do think we need to differentiate these glyphs in
order to be useful in technical documents that use greek symbols in
equations that might also use latin symbols to mean quite different things.

I think this was missed in the initial design review and needs to be
addressed pre-1.0. There may already be a dup of this, but I want to
record our firm intention to address it.

Mark

[Bruno Maag (bruno-daltonmaag)]

In the circumstances of scientific work I can see the problem with some of the characters in Greek and we will address this in the next review. Thanks for being this specific pointing this out as in a more day-to-day environment this would not really have been an issue.

Bruno

[David Marshall (dave-daltonmaag)]

The problem with artificially differentiating the execution of Greek,
Hebrew, etc. characters for the purposes of maths setting is that it
makes the setting of everyday text in those scripts look quite
preposterous - flowery for the sake of being flowery, and a result that
isn't cohesive with the rest of the font.

The way Unicode has approached it is to have a range purely for letters
for maths setting - where distinction in weight, style, script, and
appearance can be absolutely assured. The range is at U+1D400-U+1D7FF.

Dave

[adoa (adoa)]

Thank you Dave!
I had absolutely no idea, that Unicode has a special Block for this purpose. Am I right, that this block is not yet supported by the Ubuntu Font Family?

I really love the new font. But nevertheless I am quite sure I will use it exclusively on the screen. I still prefer serif fonts for my printed documents. I am sure this question is already answered, but will there be a serif version? There, I think, the differences in the glyphs are much more easy to obtain by slight changes.

[David Marshall (dave-daltonmaag)]

The maths alphanumerics block isn't on the current roadmap. I spoke to
Bruno earlier and he suggested we add just those two variant characters
to the block to help with maths setting, but obviously there are issues
with having a sparse block, and even bigger issues with the block being
beyond the Unicode BMP.

Dave

[Paul Sladen (sladen)]

Possibly less-invasive approaches:

  1. Have chi reach the descender again (it did in earlier versions; this was a vertially scaled 'x' glyph)
  2. Ensure that there *is* variation in between v and ν in the italics at least.

[David Marshall (dave-daltonmaag)]

I would say that adjusting the chi is a good idea, and that we should
explore the options for nu. In our own library InterFace makes a
reasonable distinction between nu and v without getting overly flowery,
but I can't say for sure whether the same approach would suit Ubuntu's
design. Most sans fonts don't seem to bother making a distinction as the
options are limited where there are no serifs.

Dave

[Paul Sladen (sladen)]

There's a glyph a for the current Cyrillic izhitsa ('ѵ') which shows one option (although historically I believe that this is a deriviative of upsilon rather than nu). See attached PDF for quick ideas.

[Rasmus Underbjerg Pinnerup (pinnerup)]

This bug also affects phoneticists, seing as the International Phonetic Alphabet – the universal means of notating language sounds – distinguishes clealy between [x], a velar fricative, and [χ], a uvular fricative. These are two different sounds that may distinguish one word from another, and therefore the distinction is a very important one.

Compare https://en.wikipedia.org/wiki/Voiceless_uvular_fricative and https://en.wikipedia.org/wiki/Voiceless_velar_fricative. It's absolutely necessary to fix this, or the Ubuntu font face cannot be used for describing the phonetics of languages that use a uvular stop, which quite a few do – see the first link.

[Matthew Paul Thomas (mpt)]

In a pre-release 0.84 test version, the chi character is very different from the x (bug 647092), and the nu character is *slightly* different from the v.