Repeating text watermark in background

Question

I really like the secure look of old style secure backgrounds that repeat the name of the institution in light text as a way of validating it. This is not really used anymore for secure documents but still has a nice look for things like certificates of completion.

Is there a way to do this in LaTeX? Ideally, I'd enter arbitrary text of the issuing institution ('Unseen University Physics Department') and then the command would populate the entire background of the document with that repeated phrase automatically. I tried using the xwatermark package but that seems broken, and other watermark packages are designed for one giant text superimposed on the image, which is a different look.

Answer 1

\documentclass[]{article}
\usepackage{xcolor,transparent,lipsum}
\ExplSyntaxOn
\AddToHook{shipout/background}
  {\put(0,0)
    {\parbox[t]{\paperwidth}
     {
       \Large\sffamily\transparent{0.2}\color{gray!50!white}
       \int_step_inline:nn{300}{LIMITED~ROBERT~FLEMING~\&~CO~}
     }
    }
  }     
\ExplSyntaxOff
\begin{document}
\section{some text}
\lipsum
\end{document}