[CentOS] scanner only works in su mode

Apparently I hadn't done any scanning since my move to centos.
hp-scan works for root, but not for me as me.
When I try to use xsane, it tells me no device found.
When I try to use hp-scan as myself it tells me:
error: Unable to locate device hpaio:/usb/Photosmart_C3100_series?serial=CN6ARC321S04KV using SANE backend hpaio:. Please check HPLIP installation.

What do I change to make it let me use xsane or hp-scan as myself?

This is what I get when scanning as root:
[root at localhost tmp]# hp-scan -o fred.png
warning: hp-scan should not be run as root/superuser.

HP Linux Imaging and Printing System (ver. 3.12.4)
Scan Utility ver. 2.2

Copyright (c) 2001-14 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Using device: hpaio:/usb/Photosmart_C3100_series?serial=CN6ARC321S04KV

Using device hpaio:/usb/Photosmart_C3100_series?serial=CN6ARC321S04KV
Opening connection to device...

Resolution: 300dpi
Mode: gray
Compression: JPEG
Scan area (mm):
   Top left (x,y): (0.000000mm, 0.000000mm)
   Bottom right (x,y): (215.899994mm, 296.925995mm)
   Width: 215.899994mm
   Height: 296.925995mm
Destination(s): file
Output file: /tmp/fred.png

Warming up...


Scanning...
Expecting to read 8.5 MB from scanner.
Reading data: [******************************************] 100%  8.5 MB
Read 8.5 MB from scanner.
Closing device.

Outputting to destination 'file':
Saving to file /tmp/fred.png

Done.


BTW it lied about the compression.
It gave me png.
-- 
Michael   hennebry at web.cs.ndsu.NoDak.edu
"On Monday, I'm gonna have to tell my kindergarten class,
whom I teach not to run with scissors,
that my fiance ran me through with a broadsword."  --  Lily