LuaLateX: Problem with microtype \textls and center environment

I want to use \textls to reduce letterspacing for citing works/compositions. If I use it in the titlepage inside a center environment it gets a bit messy. As in other examples, it seems like the lines somehow are moved to the right. The command inside normal text seems to work fine.

I use LuaLateX to compile.

MWE:

\documentclass{article}

\usepackage{microtype}
\usepackage{geometry}
\geometry{a4paper, top=25mm, left=20mm, right=20mm, bottom=30mm,

\usepackage{fontspec}
\setmainfont[SmallCapsFont={Latin Modern Roman Caps}]{Latin Modern Roman}

\newcommand{\work}[1]{\textsc{\textls[-50]{#1}}}

\begin{document}

\begin{center}
\huge
Immanuel Kants \work{Kritik der praktischen Vernunft},

\work{Kritik der reinen Vernunft} und

\work{Kritik der Urteilskraft}

\end{center}

\end{document}


• Remove the brace before \huge and the one before \end{center}. – egreg Oct 1 '14 at 14:49
• same problem without braces. it's not about vertical but horizontal spacing – musicman Oct 1 '14 at 14:54
• OK, retracted the vote for closing. I seem to remember that it's a problem with negative letterspacing. But the good typographical practice is to space out small caps, not the contrary. And the result in your picture is really bad, IMO. – egreg Oct 1 '14 at 15:07
• Not a solution to your issue, but just a small request: Please write Kant's, not Kants'. – Mico Oct 1 '14 at 16:02
• It seems a bug in microtype with LuaLaTeX (or a luatex bug); if I remove the call to fontspec, compiling with pdflatex or lualatex should be the same, but the problem still appears. – egreg Oct 1 '14 at 17:07

You can use the LetterSpace feature instead:

\documentclass{article}

\usepackage{microtype}
\usepackage{geometry}
\geometry{a4paper, top=25mm, left=20mm, right=20mm, bottom=30mm,

\usepackage{fontspec}
\setmainfont[SmallCapsFont={Latin Modern Roman Caps},
SmallCapsFeatures={LetterSpace=-6}]{Latin Modern Roman}

\newcommand{\work}[1]{\textsc{{#1}}}

\begin{document}

\begin{center}
\huge
Immanuel Kant's \work{Kritik der praktischen Vernunft},

\work{Kritik der reinen Vernunft} und

\work{Kritik der Urteilskraft}

\end{center}

\end{document}


You can also burry the text in a fbox with invisible rules:

\newcommand{\work}[1]{{\fboxsep=0pt\fboxrule=0pt\fbox{\textsc{\textls[-50]{#1}}}}}


It also works if you add word joiners

 \newcommand{\work}[1]{\textsc{^^^^2060\textls[-50]{#1}^^^^2060}}


but only if the text is on one line. If there is a line break centering will be lost again.

as a workaround use

    ~\work{Kritik der reinen Vernunft} und~