Cyanotypes – Saturday, 2 September 2023

On Bank Holiday Monday, we had a celebration in the garden. Some fried vegetables from the raised beds were shared around, we had a plant sale, drawing for children and cyanotype printing. The latter was organised by Max, the garden co-ordinator, and was very popular, mostly with adults but some older children had a go too.

Cyanotype printing is a simple process. You place flat objects, we used plants such as ferns and other foliage, on light sensitive paper. The objects are held flat against the paper by a sheet of glass which is clipped on to keep the items in place. And then the paper and the items are exposed to sunlight. After 10 to 25 minutes, depending on how sunny it is, the glass and objects are removed and paper is washed in cold water. This washes off any unexposed chemical, leaving white silhouettes of the objects on a blue background. The prints are then dried.

The process was invented by John Herschel in 1842. He was, incidentally, the son of William Herschel. William was the discoverer of the planet Uranus, he worked with his sister Caroline a prominent astronomer herself, the discoverer of several comets, and the first woman to receive a government salary in this country as a scientist.

The 1830 and 1840s were the early years of photography, which used silver salts that are sensitive to light. Cyanoprints does not use silver salts but two chemicals: ferric ammonium citrate and potassium ferricyanide. When mixed together in the right proportions in an aqueous solution they form a light sensitive chemical which must then be kept in the dark or in low light. It can be painted on to absorbent papers, which are dried in low light. These papers can be used to make the cyanotype prints.

The sun has been busy in other places too. Veronica used a blue acrylic in her picture on the wall of the Dare to Dream display facing Sprowston Road. And the light completely bleached it away. She was peeved at the sun’s destruction. But has decided to replace the blue with one that is not light sensitive.

This struck me, having just done a couple of cyanoprints at the workshop, that the blue acrylic could be used to make similar prints. The printing would take considerably longer than a cyanotype, days or even a couple of weeks. If kept inside, the final print wouldn’t need fixing as the breakdown of the blue is much slower. At home, I am having a go at making prints with the blue.

Light is a form of energy, which we utilise in the different forms of photography. Also in photovoltaic cells which we see on rooftops in our belated scramble to get away from fossil fuels. Here, light energy is converted into electrical energy.  Einstein received his Nobel Prize, not for his work on Relativity, but for his work on the photoelectric effect in 1905.

And of course, in photosynthesis, in which plants use light energy, as the name implies, to make sugar from CO2, water and sunlight in the chloroplasts in their leaves. This process is the basis for our food, either directly, or indirectly in the fodder fed to animals.

Last week, Thames Water came and put in a water meter and connecting pipes just outside our fence on Sprowston Road. This has been such a long saga; we have been talking about the necessity for running water at our meetings for three or more years. It’s hard to believe, but we are nearly there. The final step is a plumber connecting a standpipe in the garden to the meter.  And the water will flow.

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