diff --git a/documentation/waterfalls.sil b/documentation/waterfalls.sil
index be442701..5922380b 100644
--- a/documentation/waterfalls.sil
+++ b/documentation/waterfalls.sil
@@ -1,4 +1,4 @@
-\begin[class=fontproof]{document}
+\begin[class=fontproof,filename=LibertinusSerif-Regular.otf]{document}
 \proof[size="4,6,8,10,12,14,16,18,20",filename=LibertinusSerif-Regular.otf,heading="Libertinus Serif"]{Fox dwarves, chop my talking quiz job.}
 \proof[size="4,6,8,10,12,14,16,18,20",filename=LibertinusSerif-Bold.otf,heading="Libertinus Serif Bold"]{Fox dwarves, chop my talking quiz job.}
 \proof[size="4,6,8,10,12,14,16,18,20",filename=LibertinusSerif-Italic.otf,heading="Libertinus Serif Italic"]{Fox dwarves, chop my talking quiz job.}