In the meantime I had a look at different Fraktur fonts. Both suggested fonts [1] and [2] were not acceptable to me for various reasons.
[1] has no gaps between words and many other errors. Horrible.
Afaiks that font is rather bugged indeed. I tried it, even made sure the space (which is unspecified in the afm) is set to some value but then it seems to use maybe some ligatures which are also unspecified. Old crap.
[2] is far too fat to be printed in a book. The reason could be that the developers wanted to make a font suitable for internet presences where the resolution of screens is far below of that of printing machines. The good thing with [2] is that there is an extended and interesting set of orthography rules and their changes over various centuries beginning in 1600 up to today. But unfortunately the internet presence of [2] seems to be dead, the newest entry in member's forum I saw has been from beginning of 2017.
You can tweak it a bit:
\starttext
\definefontfeature[thinned-10][effect={width=-0.10,auto=yes}]
\definefont[ufa][unifrakturmaguntia*default] \definefont[ufb][unifrakturmaguntia*default,thinned-10]
\ufa test\par \ufb test\par
\stoptext
I'm a bit puzzled by the 'dead' remark. When a project is finished, should the author create bogus entries each year to make it look like something new is done?
[3] I found the Leipzig-Fraktur-Font, a real Easter gift :-) It's comparable to Yannis Haralambous' nice fraktur font I used for years, but in ".otf"-format. It has the slim high "s" for use at the beginning of words and within words as well as the small round "s" at the end of syllabs and words. Ok, there seems to be no "!" (Instead I use "rm !") and the sharp "ß" I had to construct by "s\hskip-1pt z". But German umlauts can be printed, for instance 'ä' by '\"a', and different ligatures, for instance 'ch', 'st', 'tz', and others exist. So, most of my necessary conditions to a Fraktur font in ConTeXt-lmtx are fulfilled. As an example is appended "Leipzig-Fraktur-Example.pdf".
ok
I thank Hans and Wolfgang for helping me.
Best make a wiki page for this (summrizing).
[1] https://ctan.org/tex-archive/fonts/ps-type1/yfonts [2] http://unifraktur.sourceforge.net/ [3] https://www.chip.de/downloads/Leipzig-Fraktur-Font_36248614.html Hans
I'd enjoy making a wiki page. Do we have a program to print caracter code tables or font tables? If not, I'd use a bundle of single \char commands to show which characters there are in a special Fraktur font. Rudolf