[Tex/LaTex] Turn \mathbb characters bold in math mode

boldmath-mode

I've seen various topics here adressing how to turn math symbols bold, but none of them gives a suitable option for \mathbb characters, as in \mathbb{ABC}.
I have tested some options to see which commands turn which symbols in bold. Here is my code:

\documentclass{article}
\usepackage{amsmath} % some math-related packages, not sure which of them are necessary
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{bm} % for \bm
\usepackage{fixmath} % for \mathbold
\begin{document}
\section{Some text $\mathbb{ABC}abc\cosh\div+\alpha$ some text} %1
\section{Some text $\boldsymbol{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %2
\section{Some text $\mathbf{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %3
\section{Some text $\pmb{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %4
\section{Some text $\boldmath{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %5
\section{Some text $\bm{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %6
\section{Some text $\mathbold{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %7
\end{document}

enter image description here

(The absence of \div in numbers 2 and 6 are not typos, neither is the 'ff' in number 3.) Apparently \pmb is the only command which turns \mathbb{ABC} bold. But it makes the characters quite ugly, take a close look: (on the right is the normal version)
enter image description here

If no alternative shows up, I think I'll just use \pmb for the \mathbb characters and \boldsymbol or something for the others.

Is there any alternative to turn \mathbb{ABC} bold?

Best Answer

Here I place three copies in close horizontal proximity by defining \fakebold{}. One can obviously modify it to use more copies, or to apply vertical offset as well. The horizontal offset is given by \bshft, currently set to 0.18pt.

By using the \ThisStyle{...\SavedStyle...} feature of scalerel, it should work across math styles, so that $\fakebold{A_b} A_{\fakebold{b}} A_b$ will give the expected result.

\documentclass{article}
\usepackage{amsmath} % some math-related packages, not sure which of them are necessary
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{bm} % for \bm
\usepackage{fixmath} % for \mathbold
\usepackage{scalerel}
\newlength\bshft
\bshft=.18pt\relax
\def\fakebold#1{\ThisStyle{\ooalign{$\SavedStyle#1$\cr%
  \kern-\bshft$\SavedStyle#1$\cr%
  \kern\bshft$\SavedStyle#1$}}}
\begin{document}
\section{Some text $\mathbb{ABC}abc\cosh\div+\alpha$ some text} %1
\section{Some text $\boldsymbol{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %2
\section{Some text $\mathbf{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %3
\section{Some text $\pmb{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %4
\section{Some text $\boldmath{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %5
\section{Some text $\bm{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %6
\section{Some text $\mathbold{\mathbb{ABC}abc\cosh\div+\alpha}$ some text} %7
What comes next is new
\section{Some text $\protect\fakebold{\mathbb{ABC}abc\cosh\div+\alpha}$ some text}%8
\LARGE$\fakebold{\mathbb{ABC}a}\mathbb{ABC}a$
\end{document}

enter image description here

and a close-up:

enter image description here