\textbf and \bf within Sans Serif

Question

I'm using \renewcommand{\familydefault}{\sfdefault} so that my entire document is in sans serif, but I'm getting peculiar results with regards to formatting.

I'm a rather sparse LaTeX user, but in the past I've always used \textbf{Super Important Text!} for bold text rather than what I've been told is obsolete; {\bf Important Junk} (which is what I first learned).

While I have that \sfdefault line in the preamble, \textbf{} is completely ignored while {\bf } is not. I suppose it wouldn't be the end of the world if the answer is that I just have to use {\bf }, but I'm assuming there's a reason you're not supposed to.

The closest solution I could find was Bold sans-serif font in LaTeX, but it dealt with section names rather than in text formatting.

EDIT: My apologies - after recreating the document bit by bit, it turns out \usepackage{charter} was causing this. The confusing part was that if I removed \renewcommand{\familydefault}{\sfdefault}, then normal boldface functionality was restored. It turns out \textbf wouldn't work iff both lines were in the preamble. Although I'm curious to know why this is, I don't need charter for the project I'm currently working on, so for practical purposes this issue has been resolved.

\documentclass{article}
\usepackage{charter}                             % If either of these two are removed
\renewcommand{\familydefault}{\sfdefault}         % There is no issue

\begin{document}
\textbf{Not bold.}
{\bf Quite Bold.}
Also Not Bold.
\end{document}

Not Bold. Quite Bold. Also Not Bold.

Answer 1

The root of the problem is a bit of a naming problem: Computer Modern's bold series is actually bold/extended, code bx, while most other fonts have an ordinary bold, code b. Your log file should tell you something like:

LaTeX Font Warning: Font shape `OT1/cmss/b/n' undefined
(Font)              using `OT1/cmss/m/n' instead on input line 6.

which translated to something readable means: "I don't have Computer Modern Sans in Bold Upright, so I'm using Computer Modern Sans in Medium Upright instead". (charter redefines bold to mean bold, not bold-extended, so that its boldface works.)

The easiest fix is probably to use \usepackage{lmodern,charter} because lmodern, while optically pretty identical to the default Computer Modern font, has a b-not-bx-bold for its sans-serif typeface.

Answer 2

It is always helpful to supply a complete small document that shows the problem. If I try:

\documentclass{article}
\renewcommand{\familydefault}{\sfdefault}

\usepackage{array}

\begin{document}

\showoutput
aaa \textbf{bbb} {\bf ccc}

\end{document}

Then the log (and the pdf result) show that both bbb and ccc are bold sans serif, using the same font:

....\OT1/cmss/m/n/10 a
....\OT1/cmss/m/n/10 a
....\OT1/cmss/m/n/10 a
....\kern 0.0
....\glue 3.33333 plus 1.66666 minus 1.11111
....\OT1/cmss/bx/n/10 b
....\OT1/cmss/bx/n/10 b
....\OT1/cmss/bx/n/10 b
....\kern 0.0
....\glue 3.33333 plus 1.66666 minus 1.11111
....\OT1/cmss/bx/n/10 c
....\OT1/cmss/bx/n/10 c
....\OT1/cmss/bx/n/10 c