The link over here http://cs.brown.edu/about/system/managed/latex/doc/bbm.pdf says

By typing \mathbold or \mathversion{bold} you switch to the bold variant of some math symbols.

But when i type \mathbold, I always get an error. Can someone please help with the commands to generate blackboard "bold" fonts using the bbm package?

1 Answer 1


You’ve found an error in the bbm manual. They meant \boldmath, a standard command to select \mathversion{bold}. So, you could set your title formatting to \bfseries\boldmath or \fontseries{bx}\mathversion{bold}\selectfont. This would give you bold math symbols to match your bold text.

A more-convenient way to select the bold version of a single math symbol is the \boldsymbol command from amsmath:

\usepackage{amsmath, bm, bbm}


  \mathbb{N}\mathbbb{N} \\
  \mathbb{R}\mathbbb{R} \\
  \mathbb{C}\mathbbb{C} \\

mathbbm sample

This aliases the bbm commands to more-standard ones used by other packages, such as mathalpha.

You can switch to sans-serif by changing the definition of \mathbb to


Which gets you

bbm sans-serif font sample

Note that the bbm fonts are in an obsolete format, and will be pixelated in a PDF file. If you want bold double-struck letters, you can load an OpenType math font with a bold version in unicode-math (such as Libertinus Math or XITS Math), and \boldsymbol{\mathbb{N}} will work. In PDFTeX, you can load


This supports \mathbbb{N} if you select a \mathbb font that comes in bold, and will get you a Type 1 outline font instead of a bitmap.

  • Many thanks for the kind help.
    – C.S.
    Oct 29, 2020 at 8:52
  • How about the sansserif bold? Could you please be kind enough to add the command line for that also?.
    – C.S.
    Oct 29, 2020 at 13:37
  • @crskhr OK, done.
    – Davislor
    Oct 29, 2020 at 13:41
  • Thanks a ton for the kind help :)
    – C.S.
    Oct 29, 2020 at 13:46

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .