Printcap IF filter not executing

[Kent West <westk@nicanor.acu.edu>]

I'm trying to better my understanding of how lprng/printcap works.
I've got an /etc/printcap entry that looks like:

lp
	:lp=/dev/null
	:sd=/var/spool/lpd/hplj3-remote
	:sh
	:pw#80
	:pl#66
	:px#1440
	:mx#0
	:if=/usr/bin/test
	:af=/var/spool/lpd/hplj3-remote/acct
	:lf=/var/log/lp-errs

The contents of /usr/bin/test are:

#!/bin/bash
echo "Here it is"

and the file permissions on /usr/bin/test are:
 -rwxr-xr-x	1	daemon 
lp 
55 Nov 26 13:41 /usr/bin/test

I can manually run /usr/bin/test and get the "Here it is" message, but 
when I try to "print" something, with a command like "lp /etc/printcap", 
/usr/bin/test appears not to run. (I realize this has no relevance to 
actual printing, but like I say, I'm trying to figure out how things work.)

Can anyone tell me what I'm missing?

Thanks!

Kent