documentclass{article}

title{Dot Paper}

usepackage{geometry}
geometry{letterpaper, margin=0mm}

usepackage{tikz}
tikzset{x=1mm, y=1mm}

definecolor{DotsColor}{HTML}{C9C9C9}

begin{document}

newsavebox{frontside}
savebox{frontside}
{
	begin{tikzpicture}[remember picture, overlay]

	color{DotsColor}

	foreach x in {0,...,42}
		foreach y in {0,...,56}
			filldraw (current page.south west) ++ (33.95,237.7) ++ (4*x,-4*y) circle (0.1);

	end{tikzpicture}
}

usebox{frontside}

end{document}