I have no experice with fonts from H&FJ, but I've licensed a few from a foundry that they collaborate with quite often. I haven't encountered anything I would call an issue (in 3 or so years, LuaLaTeX only). Technically, there isn't a difference between a commercial font and a ›free‹ one in terms of likeliness of causing trouble.
In your case, the font is probably going to be in OpenType format. That's the format pdfLaTeX isn't able to handle. You may convert the font (back) to Type1 or, if that's prohibited by the EULA, have the foundry provide you with Type1 files -- but a lot of the things that make OpenType fonts fun to use will get lost in the translation, or at least become harder to access. IMHO, there are a number of good reasons for switching to Xe/LuaLaTeX (unless you have reasons why you really can't move away from pdfTeX). Being able to use OpenType fonts is one of them.
Computer Modern isn't a font you'd want to use as a companion for Requiem, as visually, they don't have anything in common. Choose one that's rooted in the same period (the Renaissance). Minion is likely to be a good choice: you can use Minion itself for the Greek; for the math you can use one of the math packages that were made to be used with Minion (most notably Minion Math by Typoma).
unicode-math makes only sense if you also have a sensible "unicode math" font that you want to use as base math font. There is no "cm bright math" (sans serif math fonts are sparse ...). So it is better to use for the math setup the non-unicode way:
\documentclass[a4paper,12pt]{article}
\usepackage{cmbright}
\usepackage{amsmath,amssymb}
\usepackage{fontspec} % lualatex font engine
\setmainfont[Numbers = Uppercase,
Ligatures = TeX,
BoldFont = CMU Bright SemiBold,
ItalicFont = CMU Bright Oblique,
]{CMU Bright Roman}
\begin{document}
\section{Let's try!}
\textbf{Theorem 1 (Residue Theorem).}
Let $f$ be analytic in the region $G$ except for the isolated singularities $a_1,a_2,\ldots,a_m$. If $\gamma$ is a closed rectifiable curve in $G$ which does not pass through any of the points $a_k$ and if $\gamma\approx 0$ in $G$ then
\[
\frac{1}{2\pi i}\int_\gamma f = \sum_{k=1}^m n(\gamma;a_k) \text{Res}(f;a_k).
\]
\textbf{Theorem 2 (Maximum Modulus).}
\emph{Let $G$ be a bounded open set in $\mathbb{C}$ and suppose that $f$ is a continuous function on $G^-$ which is analytic in $G$. Then}
\[
\max\{|f(z)|:z\in G^-\}=\max \{|f(z)|:z\in \partial G \}.
\]
\vspace*{-1em}
\newcommand{\abc}{abcdefghijklmnopqrstuvwxyz}
\newcommand{\ABC}{ABCDEFGHIJKLMNOPQRSTUVWXYZ}
\newcommand{\alphabeta}{\alpha\beta\gamma\delta\epsilon\varepsilon\zeta\eta\theta\vartheta\iota\kappa\varkappa\lambda\mu\nu\xi o\pi\varpi\rho\varrho\sigma\varsigma\tau\upsilon\phi\varphi\chi\psi\omega}
\newcommand{\AlphaBeta}{\Gamma\Delta\Theta\Lambda\Xi\Pi\Sigma\Upsilon\Phi\Psi\Omega}
{\par \tolerance=0 \emergencystretch=100em $a\alpha b \beta c \partial d \delta e \epsilon \varepsilon f \zeta \xi g \gamma h \hbar \hslash \iota i \imath j \jmath k \kappa \varkappa l \ell \lambda m n \eta \theta \vartheta o \sigma \varsigma \phi \varphi \wp p \rho \varrho q r s t \tau \pi u \mu \nu v \upsilon w \omega \varpi x \chi y \psi z$ \linebreak[3] $\infty \propto \emptyset \varnothing \mathrm{d}\eth \backepsilon$\par}
\end{document}
Best Answer
Regular LaTeX
Finding the font name
This is actually the hardest part. When you load a regular font package like
helvet(which sets the default sans serif font to a Helvetica clone) it issues commands to set up the font using an internal name, which is hidden to regular users. These names traditionally use a system of three or four letter lower case names for each font family. Usually these names are documented in documentation associated with the font.Here is a list of the most common fonts, and their codes:
For some greek fonts the codes are:
If you don't find any documentation for the font, as a last resort (or a first resort once you know what you're doing) you can open the
.styfile that actually loads the font and see for yourself what the internal font family name is (or you could search inside it withgrep). Here are two examples:From
helvet.sty: at the end of the package is the line:This sets the default sans font (
\sfdefault) to thephvfamily, sophvis the internal name of the font.From
PTSansCaption.sty, you will find the following line:Here, the internal name is closer to its file name:
PTSansCaption-TLF.Both of these examples have shown the code for changing the default sans serif font. If the font package changes the roman or mono font you would look for the following commands respectively
Selecting the font
To select a font, you use the following commands:
It's often useful to wrap this in a macro:
Restricting the scope of the selection
You can always restrict the scope of font changing commands by enclosing the text in braces:
or if using a command
or, to make the scope of the command more visible in your file if you don't have a brace-matching editor
If this is something you will be doing a lot, it would make more sense to turn it into a proper environment:
Then you use it like any other environment:
You can also define a command corresponding to the standard font changing commands such as
\textrmor\textsf, but using your particular font:Use this like the standard commands:
An advantage of this command over the simpler version described above is automatic italic correction, cf. Why use \DeclareTextFontCommand vs. just \newcommand?.
Common fonts rendered
(except ccr Compute Concrete).