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Solargraphy

This is a work in progress article
Some time ago, Make Magazine featured an article regarding pinhole photography of the path of the sun over a six month period. The article introduced the work of Tarja Trygg, having an interest in photography I decided to have a go myself.

I had planned to have the cameras ready and in place for the winter solstice, so I could capture an entire half period of the sun, from lowest (21 December) to highest (21 June); however I didn't quite manage to get everything ready in time. The first cameras will hopefully be in position by the second week of January.


Howto: As far as I understand it...

You need four things:

  1. A beer can - you can start with a full one, but it needs to be empty to make the pinhole camera, so get drinking.
  2. A tool to cut off the top of the can
  3. Some positive (lit areas go black) photographic paper. I used Iford Harman Direct Positive Paper
  4. Gaffer / Duct tape.

Here's how you combine them.
1. Empty the beer can. It's worth rinsing it out with clean water now, else you'll probably spill beer dregs over yourself as you cut the top off the can.
2. Using a rotary cutter or scissors or some other tool, remove the top of the beer can.
3. It's worth processing several cans at once.

1. Empty beer can, your taste in beer may vary from mine.
2. Rotary cutter for removing the top of the can.
3. Can with top cut off.
4. You may want to process several cans at once if you plan to make multiple cameras.


5. Can given an internal coat of black paint.

4. I gave my cans a coat of black spray paint inside, to help kill any stray reflections, but this is entirely optional and I've no idea if it is worth actually doing.

5. Make a pinhole about half way down the length of the can. I used a 0.3mm sewing needle, I think this is large enough without being too large. I'll find out in six months... You'll need to cover the hole with opaque tape.

6. In a dark room load the paper into the camera. Matt side against the can walls, shiny side facing in to the can. The paper should be opposite the pinhole. Don't let the paper cover the pinhole. I did this step in my dark bathroom with just a red LED on a half dead battery as the only light. Let your eyes adjust to the light before you start this step.

7. As soon as the camera is loaded, cover up the open end with gaffer tape. You want it light tight. Don't be afraid to use more tape.
Update: This step is hard to do in the dark, the tape is about the same width as the hole in the can. A better idea would be to use an Aluminium pie case, which pushes in to the hole and makes a snug fit. This is then easily taped into place.

Single portion Al pie case
Fits the hole well and is easy to tape over
6. The loaded beer can pinhole camera. The pinhole is under the blue tape. The open end is sealed up with gaffer tape

Exposure

Secure the camera to something solid, and in a place where it is unlikely to attract unwanted attention (remember, you want it in the same place for 6 months). Facing south if you want to trace the path of the sun. Pull off the tape covering the pinhole, make a note of the date and time and start waiting and wondering.

If all goes well, then the size of the pinhole and the ludicrous quantities of gaffer tape sealing the camera should work to keep the worst of the weather out of the camera body and away from your photographic paper. If not, well, it's Art and you meant for it, right?

Developing

After reading around various forums and web posts relating to long-term pin-hole photography projects and solargraphy in particular, the general consensus is that you use a flatbed scanner and scan your exposed photographic paper. This sounds like madness, you'd expect the bright light in the scanner to erase and totally darken the paper. The low sensitivity of the paper used allows a shortish exposure from the scanner without totally destroying the latent image formed by 6-months exposure to the sun. It still seems like magic to me.

I scanned my papers in a dim lit room with an Epson Perfection v200 Photo scanner at a resolution of 600DPI, with a total exposure time in the scanner of about 90s. The papers were then removed to a light proof cardboard folder for storage.

The just-scanned paper, no idea why it is pink. A faint trace of image is just visible.

To really "develop" the image in the scan, I inverted and equalized the colours in Gimp 2.6 image editing software. This produces a contrast stretched, horribly rainbow coloured image. Desaturating this based on luminosity results in a reasonable looking greyscale image.

The result after processing. This is just a low-res version of the final image. Quality is better than this.

Results


Cam 1 : 10:54 2011/01/09 : 20:10 2011/06/21
Flickr Error ( ): PhotoID 5857892496



Cam 2 : 13:00 2011/01/24 Flickr Error ( ): PhotoID 5860522245



Cam 3 : Exact time and date unknown, somewhere around early February 2011 : 2011/06/19 Flickr Error ( ): PhotoID 5854384908



Cam 4 : Some time in mid-March : 2011/06/13 Flickr Error ( ): PhotoID 5853834223