Desert Island Photography

A week before a July 2017 meeting, I had a phone call asking for a short talk on “What camera would I take if I were stranded on a desert island?”
My first thought was that photography on a desert island without any of the supporting infrastructure that we’re so used to would be impossible. Film? Processing solutions? Electricity? I might take stuff with me, but once I’ve run out, what do I do?
However, when the going gets tough, the tough get going! In the circumstances, we need to keep it simple. For a start that means no enlarging, so the first requirement is that the camera should produce images at the final size – which in turn means that I should not be too demanding about the size of my pictures; my gallery is anyway going to be a small hut made of banana leaves.
My island, I have discovered, is deserted but by no means a desert. Although I am the only human, there is lush vegetation, small animals and birds, and fish in the lagoon. The essentials of life should therefore only take me a few hours a day, leaving ample time for exploration, photography, and sampling the fine wines which I shall learn to produce. The climate is subtropical, everything seems ideal, but unfortunately there is no silver mine; photography will have to be based on other chemistry than silver halides.
This raises a big problem, because nothing else is so fast. I shall have to be patient, and only photograph things that don’t move. I shall be happy with pictures 5x4”, so there is plenty of choice of cameras. I need something that packs reasonably small, and is very robust as I shan’t be able to get spare parts. A Gandolfi perhaps? – but I think there might be termites, so it needs to be metal. In a box I find an Arca Swiss monorail not being used for anything else, so there’s a good basis – strong, well-made, aluminium construction. I hope it will survive.
Now back to the speed problem. The easiest of processes to manage in the jungle would be cyanotype. Just two solutions to mix and paint on to any surface. If no paper, then leaves, wood, leather. A contact print or photogram in sunshine takes maybe 5-10 minutes, which is faster than most other non-silver processes such as dichromated gelatin. Processing is just washing with water. So when I first arrive I can bring the camera and some cyanotype ingredients, at least to get going. However, a 10-minute contact printing exposure is equivalent to a couple of days behind an f/2 lens in a camera! So no need for a shutter, fortunately for reliability.
Undaunted I set up the camera, but where to get a lens? The fastest affordable proper lens of about 20cm focal length is perhaps a Petzval Portrait at about f/3.5, but if we relax on the boring subject of aberrations, a large plano-convex lens (once part of a condenser) from the optical bits box is about 20cm f/2. Chromatic aberration is not a big problem as only blue/UV light affects the paper, but all the geometric aberrations remain. A 2-day exposure with this would alternatively need 4 days with the Petzval, over a week with a well-corrected lens such as a 210mm f/4.5 Xenar.
So here we go, and with a week’s notice for my talk I had only a couple of opportunities to get it right. The first exposure (1 day) was quite successful but a little underexposed. For the second (0.5 weeks) I allowed for the “chemical rays” by shortening the camera by 2% (4mm) after focussing visually, which probably didn’t help – and the sun got in and burnt two small holes in the paper! It was better exposed though, probably 2 days would be about right.
And when my chemicals run out? The longterm solution may be anthotype – juices from flowers, leaves or berries are painted on paper, allowed to dry, and exposed. For photograms exposures can be as short as 6 hours in sunshine, more commonly a few days. I haven’t tried it in the camera yet, but I should be able to get an image in as little as two months!

My first cyanotype negative - a continuous 27 hour exposure, the daytime mostly sunny, 20cm f/2 lens on 5x4" paper.

The same, scanned, inverted and flipped.

Is this the future of desert island photography? Anthotype photograms of Enchanter's Nightshade, made with spinach juice (6 hour exposure) and Italian red wine (5 day exposure). The faster of these might produce a direct positive in the camera in a couple of months.