# How to create a blackboard math operator as \bbsum, \bbprod, \bbint, ...?

I'd like to create a blackboard math operator as \bbsum, \bbprod, \bbint, ... ? I don't know where to begin. Could someone help me? Thank you so much Best regards. Puck

First Edit: I'm trying with \usepackage{bbold} but the result is ugly. How can I improve?

• The traditional approach is to use the metafont program. A quick and dirty solution is to draw the symbol using TikZ. OTOH, be sure to check The Comprehensive LaTeX Symbol List (CTAN). Sep 28 at 14:03
• Ok, thank you. But how?
– Puck
Sep 28 at 14:10
• font design isn't really on topic here and is a very different skill and toolset to typesetting Sep 28 at 14:11
• I've never actually used Metafont. TikZ has a manual, and you can Google CTAN (ctan.org/tex-archive/info/symbols/comprehensive/?lang=en). Sep 28 at 14:12
• In my opinion, blackboard bold fonts should be used … when writing on blackboard Sep 28 at 15:25

I agree that below suggestion is not a good idea, but it works:

\documentclass{book}
\usepackage{xcolor}
\usepackage[outline]{contour}
\newcommand*{\fancy}[1]{\color{white}\contour{black}{#1}}

\newcommand{\bbint}{\fancy{$\displaystyle\int$}}
\newcommand{\bbsum}{\fancy{$\displaystyle\sum$}}
\begin{document}
$\bbint\qquad \bbsum$
\end{document}


Output

• Why wouldn’t that be a good idea? Oct 6 at 11:52
• I thought some legends like egreg David Carlisle and Ulrike Fischer, (so many legends etc.), may give better suggestion than this, so only I said like that... Oct 6 at 12:36
• Well, none of them have provided an alternative answer. So perhaps they were satisfied with yours. Or perhaps they had other things to do. Who knows. ;-) Oct 6 at 12:40