Everything is CMR – except the LMR chapter headings in ToC

Question

I am using the following code:

\documentclass[12pt,a4paper]{report}
\usepackage[british]{babel}
\usepackage[T3,T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[activate={true,nocompatibility},final,tracking=true,kerning=true,spacing=true,factor=1100,stretch=10,shrink=10]{microtype}
\DisableLigatures[f]{encoding = T1}
\microtypecontext{spacing=nonfrench}
\usepackage{geometry}
\geometry{
    left=2cm,
    right=2cm,
    top=2cm,
    bottom=2cm,
    bindingoffset=0mm
}
\addto\captionsbritish{% Replace "english" with the language you use
    \renewcommand{\contentsname}%
    {Table of contents}%
}
\begin{document}
    \begin{titlepage}
        \vspace*{2cm}
        \centering
        {\scshape\LARGE Titlepage \par}
    \end{titlepage}

    \cleardoublepage
    \pagenumbering{Roman}
    \tableofcontents

    \cleardoublepage
    \pagenumbering{arabic}
    \chapter*{Introduction}
    This is an introduction.
    \chapter{One a}
    This is the first chapter.
    \chapter{Two a}
    This is the second chapter.
\end{document}

If I now write a document, I can begin a \chapter within the document wherever I like. The captions of the chapters after the table of contents are all writen in Computer Modern Roman bold. The captions for chapters in the table of contents – not, for example, for sections! – are written in Latin Modern Roman bold.

Why is that?

I would like to fix that so that everything is written in a Computer Modern Roman style. Expecially the bold a looks different in both fonts.

Answer 1

You are using computer modern (more precisely: the ec-fonts from cm-super) everywhere. And the a is different in different sizes by design. If you don't like it switch to lmodern.

\documentclass[12pt,a4paper]{report}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\begin{document}
 %cmr:
\bfseries \Huge a \normalsize a

 %lmr
\fontfamily{lmr}\selectfont
\bfseries \Huge a \normalsize a
\end{document}

Answer 2

If you want to stick to the cm-super fonts, an alternative is to load the fix-cm package (before anything else). It corrects most of the design flaws of theses fonts, among them the optical sizes. See its documentation for more details.

As a consequence, if you reproduce Ulrike Fischer's example, “fixed” cm-super fonts and Latin Modern fonts will look quite the same on it. That is to say, the fixed cm-super fonts will look much more like the original Computer Modern fonts.

Some glyphs will remain different though between cm-super and Computer Moder/Latin Modern, e.g. some diacritics.

\RequirePackage{fix-cm}
\documentclass[12pt]{scrartcl}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\begin{document}
 %fixed cm-super
\bfseries \Huge a \normalsize a

%lmr
\fontfamily{lmr}\selectfont
\bfseries \Huge a \normalsize a
\end{document}