An Inexpensive Gel
Documentation System
Tony Schountz, PhD
School of Biological Sciences
University of Northern Colorado
[email protected]
http://www.unco.edu/schountz/gel/
Revision 3.2 16 Oct 2006
Commercially-available gel documentation
systems cost US$2,000 or more, but usually
have software for sophisticated gel analysis.
This document describes the assembly of a
gel documentation system (image capture) for
about US$250. It requires basic skills in
power tool use to build a light box for a
commercially-available digital camera, the
The idea for this system was adapted
from one used by the Hirsh Lab
http://www.virginia.edu/biology/Fac/hirs
h_gel/gel/
Although this system is working for me,
I offer no
Camera Equipment
(Can be purchased from B&H Photo*)
•
Canon PowerShot A520
(B&H #CAPSA520) - $170
•
LA-DC52F
52 mm filter adapter for A520 (B&H #CALADC52F) -
$18
•
52 mm UV filter
(B&H #BWUV52) - $20
•
52 mm infracolor 099 orange filter
(B&H #BW09952) - $20
•
1/4” Tripod screw
(B&H #LI861568 or Home Depot) - $4.50
•
ACK-800 AC Adapter Kit
(B&H #CAACK800) - $40 (optional -
eliminates the need for camera batteries)
B&H Photo http://www.bhphoto.com/ *I have no financial interest in
Canon PowerShot A520
•
PowerShot A520 Body (4 megapixels)
•
MultiMediaCard memory card
(included with most cameras)*
•
2 AA Alkaline Batteries
•
Canon Digital Camera Solution
CD-ROM
•
USB Interface Cable
Needed items included with the camera
*There is no need to purchase a larger memory card because the images are stored on your hard drive, not
Camera Note
Although this document discusses the use of the
PowerShot A520
, other Canon cameras should work, so
long as there is a
filter adapter
for the camera. So
far, we have used three Canon cameras with success,
the PowerShots A520, A95 and A70. These are no longer
in production, but Canon offers others with similar
prices and features. For additional information, see
Canon’s web site:
Software
•
Canon Digital Camera Solution Disk
(included with the Canon camera)
•
ImageJ
-
http://rsb.info.nih.gov/ij/
•
Gel-converter.class plugin
for
ImageJ, available at the Hirsh lab
web site
Hardware
•
USB-equipped Mac (OS X) or Windows PC
•
Transilluminator
•
Five sided box (1/2” width boards) with 2.25”
hole in the top to accommodate the camera filter
adapter
•
1/2” Weather stripping
•
L-bracket with 1/4” hole for tripod screw (e.g.,
Home Depot)
•
1/4” nut for the tripod screw (to secure it to the
L-bracket)
•
Handles for the sides of the box
•
#6 x 3/4” screws for holding the box together; #5
Tools
•
Table, circular, or jig saw
•
Straight edge for cutting guide
•
Drill and bits
•
Screw driver
•
Optional:
Router with flush-trim
bit
•
Optional:
Random orbit sander/220+
Box Construction
•
1/2” Medium-density fiberboard (MDF; Home Depot,Lowes, etc.).
•
10”d x 11”w x 10”h. I cut four 10”x10” boards for the sides and a 10”x11” top. You’ll need to custom-design a box to fit your transilluminator. The height should be enough so that the camera can see all of the glass on the transilluminator. I used a router with a flush-trim bit to get nice smooth edges.•
Held together with wood glue (probably not necessary) and countersunk #6 x 3/4” wood screws. Pre-drill the holes for the screws. Use a hand-held screwdriver, andnot a powered screwdriver, to tighten screws in MDF. Do not over-tighten!
•
2.25” hole for filter adapter was cut with a hole saw(about $11 from Home Depot) for power drill.
•
Lightly sand the outside surfaces. Prime, then spray-paint flat black inside and outside. This is important because it eliminates reflections and flare inside the box.•
Handles attached with screws only.•
1/2” weather stripping on bottom edges to protect the transilluminator glass.•
L-bracket screw hole drilled out to 1/4” toaccommodate tripod screw. Important: Mount the
L-bracket to the camera before marking the drill holes for mounting the bracket to the box. This is necessary because the filter adapter protrudes into the box. Use appropriate screws for the L-bracket (I used #5 x 5/8” wood screws).
Here’s how I made my camera box1:
1 Note: If you don’t have access to a
power saw or are uncomfortable using one, most home centers (such as Home Depot or Lowes) will custom cut MDF to size for a small price. Usually, the first two cuts are free, the rest are about $1 each. The accuracy of these cuts are adequate for box construction.
System Assembly
•
Attach filter/lens adapter to camera•
Attach UV filter to adapter•
Attach orange filter to UV filter•
Thread tripod screw through L-bracket, then onto thecamera. Visually align the camera so that it is
perpendicular to the
transilluminator glass.
•
Position the box on thetransilluminator Note the USB and power adapter cables are plugged into
the camera. The Maxell AC 3000 power adapter (Circuit City), pictured above, is plugged into the outlet (red box) and connected to a PowerShot A70. The PowerShot A520 has a 3.2 V requirement. The AC 3000 has a voltage setting (3.3 V) close to the A520’s requirement. The Canon ACK-800 adapter is about $7 more than the AC 3000.
Other Canon cameras have different voltage requirements, so exercise caution when setting the voltage on the adapter.
System Setup
•
Install the
Canon
software
•
Install the
ImageJ
software
•
Install the
gel_converter.class
plugin into ImageJ’s
plugin folder
•
Connect the camera to a USB port
•
Make sure the camera is set to
Playback Mode
using the
Mode Switch
•
If you’re using Mac OS X, open the application
Image
Capture
. In the Preferences, set the camera connection
option to open the
CameraWindow
application found inside
the Canon directory. Quit Image Capture. From now on,
anytime the camera is turned on, CameraWindow should
automatically launch.
CameraWindow
•
Canon software utility that controls the camera fromthe computer
•
After it opens, click onRemote Shooting
•
Click on the icon forStarts Remote Shooting
•
You’ll be prompted forwhere the image files are to be saved.
Remote
Shooting
•
The RemoteCapture Task application is used for capturing gel images•
You should see a live video of what’s on the gel box•
Adjust the gel’s position so that it’s roughly centered in thevideo window
•
Zoom using the zoom slider•
Set all the parameters for Size and Resolution (set to SS for small-superfine here), Rotation Setting, and the Field angle/flashsettings as shown in the picture
Zoom Slider Size and Resolution Rotation Setting
•
Adjust other settings in theShooting settings tab. You may want to adjust some of these
settings to suit your needs. We set Photo Effect to Black & White
and sometimes switch AE Mode to
Manual if we have dim bands.
•
When the gel is properly framed, click the Release button(encircled)
•
The image will be saved in thefolder you selected at application launch
Remote
Example Gel Capture
This image was reduced to 640x480 from the original 1024x768, but otherwise unaltered.
Gel Editing
•
Open the gel file inImageJ
•
Crop and rotate as desired•
Run the Gel Converterroutine from the
Plugins pull-down menu
•
Scale the image as necessary•
The Gel Converter routine produces an inverted grayscale image of the gelNote: By inverting the grayscale, less ink or toner will be used when the image is printed.
iPhoto
•
You can import gel files into iPhoto for easier management.•
Choose File > New Album•
Choose File > Add to Library...•
Select files to import•
Drag and drop the image files into the newly created album•
iPhoto will provide you with exposure information as well as date and time the photo was taken.•
iPhoto can also convert the color images to black and white,and it performs basic image manipulations, such as cropping and contrast.
Notes
•
Be sure to get the correct lens/filter adapter for the Canon camera that you purchase.•
The orange 099 filter is not a narrow bandwidth filter. Narrow bandwidth filters are substantially more expensive ($200+), but probably give a little better image.•
Our system is used with an iMac G5 (OS X 10.4.3) and Canon software CD version 19.•
Comments, suggestions, questions and complaints can be emailed to me. I’ll do my best to answer questions and addresscomplaints.
