LaTeX Font Warning: Font shape `…' undefined — Font shape substituted

The font lacks a requested shape (e.g. bold small caps) and another one was used.

Fix

Use a font family that has the shape, or avoid the combination.

Reproduced on TeX Live 2026 by CI · pdflatex · corpus/font-shape-substitution

Bold small caps not available in the font

Fails: main.tex

\documentclass{article}
\begin{document}
\textbf{\textsc{Algorithm 1}} computes the fixed point.
\end{document}

Fixed

\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
\textbf{\textsc{Algorithm 1}} computes the fixed point.
\end{document}

What TeX prints in main.log

LaTeX Font Warning: Font shape `OT1/cmr/bx/sc' undefined
(Font)              using `OT1/cmr/bx/n' instead on input line 3.