Re: Variable pitch text filling

[Yuan Fu]

> Yes, if we're distributing the extra space on the space characters only,
> we can use space specs.  But usually typesetters don't do that -- they
> also distribute some of the space between other characters, too, to get
> a more even "greyness".  (Or whatever they call it -- it's been a few
> years since I read up on typography last time.)

I think they call it “color”. Typography people surely know how to name things. 
And what you described seems to be tracking, ie, altering the space between 
individual characters.

Yuan