# Blackboard bold greek letters

I have the need to use greek blackboard bold letters and for this reason I checked this question and solved the package superposition problem thanks to the answer on this other question.

The problem is that I personally don't like the appearence of the bbold package font and I was looking for something like this (I don't see the bottom part of the image with the greek letters in my computer, but it's clearly visible on google images just typing the title of the question; if you have the same problem see here)

So I deduce that another type of blackboard bold greek font doesn't exist yet, am I right? Or maybe I just cannot find it? Thanks!

• Thanks for the bonus! Sep 23 '20 at 12:03
• It's the minimum I could do, you solved me a big problem: the problem became important when I had to write Dirac equation with $\alpha,\beta,\gamma,\sigma$ matrices and at the same time using $\alpha,\beta\gamma$ to indicate components of matrices, matrices for which normally I used '\mathbb' with latin letters until that point. I didn't really know what to do and to change my whole typographic convention (how anyway?) was not thinkable. Thanks a lot again! Sep 23 '20 at 12:33

The OP cites this question, Who can write a package for the new mathbb font as in the picture and compatible with Computer Modern font?, as a desired endpoint, in which it appears that an outline font is offered.

For work in pdflatex, and adapting my answer here: Outline text using TrueType fonts, you can set color of border, fill and line-thickness metric, and use pdf specials to accomplish the outline.

\documentclass{article}
\usepackage{xcolor}
\input pdf-trans
\newbox\qbox
\def\usecolor#1{\csname\string\color@#1\endcsname\space}
\newcommand\bordercolor[1]{\colsplit{1}{#1}}
\newcommand\fillcolor[1]{\colsplit{0}{#1}}
\newcommand\outline[1]{\leavevmode%
\def\maltext{\mydelim #1\mydelim}%
\setbox\qbox=\hbox{\maltext}%
\boxgs{Q q 2 Tr \bbthickness\space w \fillcol\space \bordercol\space}{}%
\copy\qbox%
}
• @Rob Fine. Yes the syntax is a bit clumsy but works fine. If you only need a few mathbb greek letters defining a command is the way to go to be sure the syntax is OK. Sep 23 '20 at 8:05

If you have an outline font, in TrueType or OpenType, that supports Greek letters, you can load it in unicode-math with

\setmathfontface\varbb{SomeFont-Outline.otf}[
Scale=MatchUppercase]


Unfortunately, I don’t have a good example at hand of a free outline font with Greek letters.

One disadvantage of doing things this way is that unicode-math might try to find the Unicode mathematical alphanumeric symbols (such as U+1D8FC, 𝛼) instead of the regular Greek letters (such as U+03B1, α). Since you’re loading a display font, not a math font, it will only have the regular letters. To work around this, you might need to type \varbb{\mupalpha}, \varbb{\mupTheta} and so on instead of \varbb{\alpha}. Or I guess you could write a function in expl3 to remap the input.

The \symbfup or \symbfit alphabet might be a good substitute. In PDFTeX, the isomath package also allows you to select an OML font, which support Greek, for your bold upright and bold italic alphabets.

• I think I understood most of it, but sorry I don't get "You might additionally want to have the command select \symup, so that \varbb{\Theta} looks for the correct Unicode character. Otherwise, you might need to write \varbb{\mupTheta}." I tried for example to read here mirrors.ibiblio.org/CTAN/macros/latex/contrib/unicode-math/… but I don't get what '\symup' command should do Sep 22 '20 at 13:27
• @Rob That paragraph wasn’t correct and I’ve changed it. Sep 22 '20 at 21:38
• Now I understand better, but as you say the problem is to find the font! Sep 23 '20 at 7:57
• @Rob It’d be possible to start with the bold Greek letters of Latin Modern Math, or maybe CMU Serif, and turn them into an outline or stencil. Sep 23 '20 at 11:11
• Sure, but I have no idea how ahah is it something like the main answer of the question? Sep 23 '20 at 11:54