# Abbreviations in mixed cases in small caps

Some guidelines suggest the use of use small caps for abbreviations. I have an issue with the following one: iTRAQ. Here are some guidelines on mixed small-upper case abbreviations. I do want to keep the small-caps version visually as close as possible to the standard one.

iTRAQ, i\textsc{traq}, and i\kern.07em\textsc{traq} look like this with the font charter:

The i in the two capitalized versions is larger than the small-caps afterwards and also TRAQ is lighter than the other text. Is there a good general solution for mixed-case abbreviations?

Update 1. Charter does not use real small caps, but scales the font, that's why TRAQ is so light. With kpfonts, which has true small caps, it looks slightly better, but still strange as the i is larger than the caps:

Update 2. Using Barbara Beeton's/tugboat's solution, I am happy with the result (second variant in the image):

Using small in normalsize environment, etc., to have fake (or true?) small-caps produces an results which is, for my eyes, visually appealing. The abbreviations are slightly lighter than true small-caps, but I can life with that for the benefit of having an universal solution.

• Small caps is only a suggestion, and ought to be ignored when not appropriate, as I think is the case here. To be perfectly honest, I think the lowercase i is an affectation, unless this is a trademark. – Dan Dec 8 '13 at 4:17
• Unfortunately it is a [trademark][de.wikipedia.org/wiki/ITRAQ], and people would recognize it in that writing style with lower-case i. The text in which I use this abbreviation is long and contains many more abbreviations - I guess I use small caps either for all or none? – Florian Bw Dec 8 '13 at 9:22
• because all caps is too overwhelming, and ordinary small caps are felt to be too small, tugboat uses a command called \SMC (accessed by a derivative command \acro) to set caps one size smaller (but still using caps). the code is fairly involved, but we like the results. see the file ltugboat.cls; it is included in a full tex live installation, or can be found on ctan. – barbara beeton Dec 8 '13 at 15:51
• That indeed is a nice solution, @barbarabeeton! I have the same feeling regarding the sizes, small-caps do stand in many fonts as very small. Furthermore, as there is no big difference between normal-small, etc., the small-caps are also not too light when using your approach (in contrast with sc carter, for example). Could add an answer which I'd be glad to accept? – Florian Bw Dec 9 '13 at 17:49

CW from the comments: The TUGboat solution:

\documentclass{article}
\makeatletter % code from ltugboat.cls:1477-1494
\DeclareRobustCommand{\SMC}{%
\ifx\@currsize\normalsize\small\else
\ifx\@currsize\small\footnotesize\else
\ifx\@currsize\footnotesize\scriptsize\else
\ifx\@currsize\large\normalsize\else
\ifx\@currsize\Large\large\else
\ifx\@currsize\LARGE\Large\else
\ifx\@currsize\scriptsize\tiny\else
\ifx\@currsize\tiny\tiny\else
\ifx\@currsize\huge\LARGE\else
\ifx\@currsize\Huge\huge\else
\small\SMC@unknown@warning
\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
}
\newcommand{\SMC@unknown@warning}{\TBWarning{\string\SMC: nonstandard
text font size command -- using \string\small}}
\newcommand{\textSMC}[1]{{\SMC #1}}
\newcommand{\acro}[1]{\textSMC{#1}\@}
\makeatother
\newcommand{\iTRAQ}{i\acro{TRAQ}}

\begin{document}
This is an example of using \iTRAQ\ in running text.
\end{document}