classicthesis and scrheadings

Question

When using classicthesis I feel that the spacedlowsmallcaps (provided by classicthesis) take too much control over my typography. I've been able to tweak the section titles to have a capital letter in the beginning. However, I don't seem to be able to get the text in the header to be anything but small caps. Is it possible to customize this?

Any help on this would be highly appreciated!

Here is what I am working on - and I use LuaLaTeX:

\documentclass[twoside,openright,titlepage,numbers=noenddot,headinclude,
            % headlines,% letterpaper,% a4paper
            footinclude=true,cleardoublepage=empty,
            BCOR=5mm,paper=a4,fontsize=10pt]{scrbook}
\usepackage{lipsum}
\usepackage{amsmath,amssymb}
\usepackage[math]{fontspec}
\newfontlanguage{Norwegian}{NOR}
\defaultfontfeatures{Ligatures=TeX,Numbers=OldStyle}

\usepackage{subfig}
\usepackage{titlesec}
\usepackage[parts,beramono,eulerchapternumbers,%
        listings,subfig,manychapters,%
        floatperchapter]{classicthesis} 

\begin{document}
\titleformat{\section}{\relax}{\textsc{\thesection}}{1em}{}
\pagestyle{scrheadings}
\chapter{First chapter}
\section{First section}
\lipsum[1-6]
\newpage
\lipsum[1]
\end{document}

Answer 1

The answer depends on your objective: If you want to use some other font features at all places where classicthesis uses spacedsmallcaps the easiest is just to redefine the command: \DeclareRobustCommand{\spacedlowsmallcaps}[1]{\itshape #1} would use simple italics instead of small caps.

If you want to redefine it just for the headers you need to redefine the appropriate command as I demonstrate in the MWE:

\documentclass[twoside,openright,titlepage,numbers=noenddot,headinclude,
            % 1headlines,% letterpaper a4paper
            footinclude=true,cleardoublepage=empty,
            BCOR=5mm,paper=a4,fontsize=10pt]{scrbook}

\usepackage{lipsum}
\usepackage{amsmath,amssymb}
\usepackage{subfig}

\usepackage[parts,beramono,eulerchapternumbers,%
        listings,subfig,manychapters,%
        floatperchapter]{classicthesis}

% This redefines space low caps completely
% \DeclareRobustCommand{\spacedlowsmallcaps}[1]{\itshape #1}

% This redefines just the header just for chapters
\renewcommand\Chap[2][]{%
                     \ifluatex\oldchap[\texorpdfstring{\textit{#1}}{#1}]{#2}%
                     \else\oldchap[\textit{#1}]{#2}%
                     \fi%
}

% Fontspecs needs to be loaded AFTER classicthesis
\usepackage[math]{fontspec}
\newfontlanguage{Norwegian}{NOR}
\defaultfontfeatures{Ligatures=TeX,Numbers=OldStyle}


\begin{document}
\titleformat{\section}{\relax}{\textsc{\thesection}}{1em}{}
\pagestyle{scrheadings}
\chapter{First chapter}
\section{First section}

\lipsum[1-6]
\newpage
\lipsum[1]
\end{document}
% ********************************************************************

Note the following:

• It's documentclass, not Documentclass
• Fontspec must be loaded after classicthesis
• No need to load fontspec twice
• In this MWE I just redefine the headings for chapters. You may want to to the same for tocEntry and PartS.