diff --git a/etc/nsxiv.1 b/etc/nsxiv.1
index d601e5c..a75a0a0 100644
--- a/etc/nsxiv.1
+++ b/etc/nsxiv.1
@@ -457,6 +457,9 @@ Color of the bar foreground. Defaults to window.foreground
 Color of the mark foreground. Defaults to window.foreground
 .TP
 Please see xrdb(1) on how to change them.
+.LP
+An X resources entry with an empty value means the default
+(defined in config.h) will be used.
 .SH WINDOW TITLE
 The window title can be replaced with the output of a user-provided script,
 which is called by nsxiv whenever any of the relevant information changes.