I am working on a document which invokes both fontenc and lmodern, and ran into a problem with producing bold smallcaps.
I came across this post: How te get bold + small caps with latin modern or computer modern which offers a (Xelatex) solution with the fontspec package---but as I am invoking fontenc (and am compiling with pdflatex)---an adaptation of that solution to my situation would be out.
Nevertheless, after looking at the OP's MWE, I have obtained the following MWE:
\documentclass{book}
\usepackage{xcolor,lettrine}
\usepackage[T1]{fontenc} % Needed to make the letters folloiwng the lettrine boldface.
\input GoudyIn.fd
\newcommand*\initfamily{\usefont{U}{GoudyIn}{xl}{n}}
\usepackage{lmodern}
\usepackage{fix-cm}
\rmfamily
%\DeclareFontShape{T1}{lmr}{b}{sc}{<->ssubcmr/bx/sc}{}
\DeclareFontShape{T1}{lmr}{bx}{sc}{<->ssubcmr/bx/sc}{}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[lines=3,loversize=.25]{\initfamily{T}}{\textbf{he}}
\end{document}
which seems to work (though I have some questions):
Note: The OP makes use of both of commands: \DeclareFontShape{T1}{lmr}{b}{sc}{<->ssub*cmr/bx/sc}{} and \DeclareFontShape{T1}{lmr}{bx}{sc}{<->ssub*cmr/bx/sc}{}; though I have found that \DeclareFontShape{T1}{lmr}{bx}{sc}{<->ssub*cmr/bx/sc}{} alone works for me. (The only difference I see between the two is {b} vs. {bx}).
QUESTION: Can anyone tell me (when compiling with Pdflatex), the difference between the two; if both are needed for the purpose of obtaining bold smallcaps when \lmodern is invoked; and if, perhaps, there is a better way of accomplishing this than this approach which does seem to work without using fontspec, as I am precluded from so doing by the use of fontenc and pdflatex?
Thank you.

lmodernsmallcaps problem is OK then? I couldn't find what seemed like a "canonical" method, so I figured I would give this a try. β DDS Aug 25 '22 at 19:17cmrinstead oflmodernif you need its features, or you might use commands such as here to format your lettrines, if that is where you need them. β Davislor Aug 25 '22 at 21:01