Camera obscura with a 12 foot focal length and a 5mm pinhole which makes it about f/732. Exposure of about 9 hours with a Crown Graphic 4x5 and 135mm lens at f/4.7 on Ilford HP5. Developed in Dektol stock diluted 1+9 for 9 minutes at 20°C. Negative was much better.
The light bit on the left is me leaving the room after I opened the shutter. If you look close to the snow lined wall (top), you can see it melted during the day which gives a transparent quality.