The program:
Code: Select all
\documentclass[12pt,a4paper]{book}
\usepackage{xcolor}
\usepackage{lipsum}
\usepackage{setspace}
\renewcommand{\baselinestretch}{1.5}
\begin{document}
\lipsum[1]
{\setstretch{0.5}\color{blue}
\lipsum[2]
}
\lipsum[3]
\end{document}
Greatings Jan Borowiec