Solargrams chart the passage of the sun through the sky. The image is built up over the period of exposure which can range from a single day, to over a year. The arbitrary colours are purely the result of the process.
Further information about creating solargrams with pinhole cameras
A few examples from an ongoing project:
long duration
solargram ryb03 sunrise 2012-07-19...2012-12-08
5 litre paint can camera mounted on the eastern apex of my barn wall
solargram ryb02 midday sun 2012-07...2012-12
Film canister camera facing due south on garden wall.
Rain entered the camera during the 5 month exposure and caused the emulsion to disintegrate and mould to form on the paper: another indication of the passage of time...
summer / winter solstices
Most years I try to install at least one solar camera to capture the summer solstice, either sunrise or sunset. Sometimes, I'm able to catch the winter solstice too (weather permitting!) The sun's path hardly changes over the period of a week either side of the solstice, and this allows a typical two-week exposure to generate an almost complete single arc across the sky, even if weather conditions are unfavourable some days.
The tiny film canister cameras are ideal for this as they can be wedged in somewhere unobtrusively, and if they're lost or damaged, it doesn't matter. I've had cameras dislodged by sheep, pecked out by birds and otherwise disturbed by the forces of nature. But they always manage to capture something; a record of their experience at a particular place and time. It is the tension between the predictable and perpetual rotatation of the earth and the fragility of our own existence which is the essence of solargrams.
solargram haf01 2022 midsummer sunrise at Bird Rock, Hafen, Mid Wales.
The rock is so named because the top section appears very bird-like from a certain angle!
[film canister camera: 2022-06-19...2022-07-01]
solargram pum01 2021 midsummer sunset at the source of River Severn / Afon Hafren
The source marker post can be seen beneath the sun's arc on the right of the photo.
[film canister camera: 2021-06-14...2021-07-01 ]
solargram tbd13 2020 midsummer sunrise through wire fence, Trembyd, Mid Wales
[film canister camera: 2020-06-13...2020-06-28]
solargram tbd10 2018 midwinter sunrise through the Blackstone Hay Rake, Trembyd, Mid Wales.
[film canister camera: 2018-12-14...2018-12-29]
solargram tbd08 2017 midsummer sunrise through the Blackstone Hay Rake, Trembyd, Mid Wales.
Slight movement of the camera (no doubt due to sheep) has caused the double image.
[film canister camera: 2017-06-11...2017-07-01]
solargram dgf05 2016 midsummer sunrise over Drygarn Fawr in the ancient heart of Wales.
[film canister camera: 2016-06-16...2016-06-30]
solargram ddu01 2016 midsummer at Drum Ddu, Mid Wales
Using a camera with 3 pinholes, spaced 120° apart. These face S, NW & NE (approximately)
and collect all of the sunlight in the period in 3 overlaid traces.
I think of this as another version of all the light!
[360° 3 hole camera 2016-06-18...2016-06-26]
solargram tbd05 2015 midsummer sunrise, at the top of Trembyd, Mid Wales (450m)
[film canister camera: 2015-06-16 ... 2015-06-28]
solargram har01 2013 midsummer sunset, Hartland, Devon
[film canister camera: 2013-06-18...2013-06-25]
miscellaneous
solargram haz04 View due south from the overgrown remains of the lost village of Hazelford, Oxfordshire.
A mysterious halo surrounds the distant objects.
[film canister camera: 2013-10-12 ... 2013-12-30]
solargram har03 Brenda's garden, Hartland, Devon (For pinhole day 2015)
[film canister camera: 2015-01-02 ... 2015-04-26 ]