I'm currently using these packages in my document:

\usepackage{amsmath, amsthm, amssymb, amsbsy}

But when I try to use:


As and example, well, nothing happens. It's not bold. I've also tried \mathbf and such. But nothing happens.

I don't know if it is because I'm using the "Times New Roman"-like package ?

Can anyone help me out?

  • 1
    Yes, the reason is mathptmx; try \usepackage{newtxtext,newtxmath}, if you have an up-to-date TeX distribution.
    – egreg
    May 31 '13 at 22:09
  • The documentation for the mathptmx package says: · There are no bold math fonts, and \boldmath has no effect. May 31 '13 at 22:09
  • ^^ So what you are saying is, that there is nothing I can do about it ? The \usepackage{newtxtext,newtxmath} doesn't seem to work either. May 31 '13 at 22:13
  • \mbox{\boldmath$\sigma$} should work. I use this all the time for bold Greek letters. If it works for you, I will make it an answer.
    – dustin
    May 31 '13 at 22:14
  • ^^ Nope, it does not :/ I'm just doing: \begin{equation} \mbox{\boldmath$\sigma$} =\frac{\mathbf{j}}{\mathbf{E}}, \label{eq:3.1} \end{equation} May 31 '13 at 22:16

As a last resort, over-printing (or under-printing) as a method to simulate boldness (or fake bold) is an option using the contour package. It may come in handy when there is no bold version of a font/symbol available:

enter image description here

\usepackage{mathptmx}% http://ctan.org/pkg/mathptmx
\usepackage{array,contour}% http://ctan.org/pkg/{array,contour}
\verb|\sigma|: & $\sigma$ & $\sigma$ \\
\verb|\contour[1]{red}{$\sigma$}|: & \contour[1]{red}{$\sigma$} & \contour[1]{red}{$\sigma$} \\
\verb|\contour[10]{black}{$\sigma$}|: & \contour[10]{black}{$\sigma$} & \contour[10]{black}{$\sigma$} \\
\verb|\contour{black}{$\sigma$}|: & \contour{black}{$\sigma$} & \contour{black}{$\sigma$} \\
\verb|\contour*{black}{$\sigma$}|: & \contour*{black}{$\sigma$} & \contour*{black}{$\sigma$}

The default interface is \contour[<number>]{<color>}{<stuff>} that prints <number> copies of <stuff> under <stuff> using colour <color>. The default is 16 repetitions if none are specified, while the starred-version \contour* prints 32. \contourlength{<len>} sets the radius of the under-printing. The two column above are default (0.03em) and 0.01em.

To make the under-printing more obvious/clear, here's a close-up view of the above contours at the default setting:

enter image description here

And, for \contourlength{0.01em}:

enter image description here

  • And there we have it :) A bit of a workaround, but it works :) Thank you :P May 31 '13 at 22:36
  • \newcommand{\contourbbms}[1]{\text{\contour[2]{black}{$#1$}}} if you use it in equations for one symbol, you'd better create a new command. You should put the contour command in \text{}. Then you use it as $\contourbbms{\sigma}+\sigma=2\sigma$. But I run xelatex twice then I get the bold symbol. Anyway it works.
    – Nick Dong
    Jul 26 '19 at 16:19

With newtx you can get bold math symbols; the text font is very similar to what you'd get with mathptmx and the math fonts are surely much better.





Note that \boldsymbol provided by the amsbsy package is to be considered obsolete as \bm is much better.

enter image description here


I have amsfonts loaded:

An ex­tended set of fonts for use in math­e­mat­ics, in­clud­ing: 
ex­tra math­e­mat­i­cal sym­bols; black­board bold let­ters (up­per­case only); frak­tur let­ters; 
sub­script sizes of bold math italic and **bold Greek let­ters**; 
sub­script sizes of large sym­bols such as sum and prod­uct; 
added sizes of the Com­puter Modern small caps font; 
cyril­lic fonts (from the Univer­sity of Wash­ing­ton); Euler math­e­mat­i­cal fonts. 

Even though you say it didn't work, it is working fine on my end.

 \begin{equation} \mbox{\boldmath$\sigma$} =\frac{\mathbf{j}}{\mathbf{E}}, \label{eq:3.1} \end{equation}


enter image description here

as you can see I just added real quick to a document I am working on.

Here is a regular sigma next to it. enter image description here


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