Tidal Impressions
of the River Thames

The installation revisits Anna Atkins’ album from 1843–52 entitled Photographs of British Algae: Cyanotype Impressions. The cameraless process of “blueprint” or “sunprint” was invented by Sir John Herschel in 1842. Using a similar sheet size and the same chemical processes as Anna Atkins, I made blueprint photograms of the debris gathered from the foreshore. The bits and pieces were placed in direct contact with the photographic material and exposed to sun on a paper coated with light sensitive iron compounds. The marks left by the objects turned into permanent deep blue renditions when the papers were developed by rinsing with water.

Debris from the foreshore was displayed on metal shelves under a row of cyanotypes that fixed the shadows and enhanced the traces left by the very pickings. A thin line of black gaffer tape marked a zero-meter level on the gallery walls. The shifts in distance between the rows of blueprints and the 0m line indicated relative variations in the level of low tides during my 33 days of mudlarking. The respective high tides were displayed through 33 measurement tapes rolled out against the wall.