Solargraphy is an alternative photography process that uses homemade pinhole cameras and traditional light-sensitive black and white photo paper to capture very long exposures of the sun's movement across the sky. Over days, weeks, months and even years, a single image is constructed, revealing a view of space, time and weather patterns that we are otherwise not able to see. The exposed sun paths show a gradual day-to-day change due to the Earth's slightly elliptical orbit and its 23.4° axial tilt. The height of the paths is based on the latitude the image was made. Missing or broken paths are the results of periods when clouds have obscured the sun.
The colours are not a straight depiction of the scene but a consequence of the paper's chemical reactions to extreme overexposure and the influence of uncontrollable factors such as moisture, dirt or fungus that may have invaded the camera, as well as extreme temperature fluctuations. Additionally, each brand of photography paper has a different chemical makeup which results in a different colour scheme.
Due to the long exposure, the paper should not be developed as it would turn completely black, and using fixer will remove much of the colour. Instead, a high-quality flatbed scan is made of the "negative" even though the paper is still light sensitive. This means that the light from the scanner will degrade the image as it works its way across the paper. The image is then inverted, horizontally flipped, and colour and tonally processed in Lightroom and Photoshop.