[XeTeX] letter spacing

[Adam Twardoch]

Jonathan Kew wrote:
> I'd usually agree with those who consider letterspacing a Bad Thing,
No no no. Letterspacing of lowercase is generally considered a Bad Thing.

Letterspacing of uppercase and small caps is usually considered a Good 
Thing, and actively recommended by many renowned typographers 
(Bringhurst, Tschichold, Willberg). This is mostly because the default 
spacing of capital letters is optimized for use in mixed-case setting. 
In all-caps setting, the natural spacing of the letters often turns out 
to be too tight.

I don't know much about TeX and am now actually quite surprised to hear 
that there is no standard tracking control in TeX. Tracking is an 
essential ingredient of typographic design. Good typographic design 
usually involves adding and removing some interletter whitespace 
depending on the point size. Especially when using a font that doesn't 
have independent optical masters, you'd slightly increase tracking in 
small sizes and slightly reduce it in large sizes. This has always been 
a common practice.

The "cpsp" OpenType feature does not solve the task because it only 
offers a fixed tracking change for all caps settings. This is useful 
(provided the designer has included this information in the font anyway) 
but on top of that, the user ALWAYS needs to track. It can't be an 
"on/off" thing, you need to be able to specify both the positive and the 
negative amount. Of course, in most cases, the tracking changes are 
small (0.5-4% of the em).

For some reason, I always assumed that this would be a trivial thing to 
do in TeX. I guess it's one of the myths of "excellent typographic 
control offered by TeX" that actually turns out to be false :/

-- 

Adam Twardoch
http://www.twardoch.com/