PHOTOGRAPHING AQUATIC SPECIMEN-"OLD SCHOOL STYLE"- CYANOTYPE WORKSHOP
Escola Secundária de Loulé, Loulé, PORTUGAL
In the activity "PHOTOGRAPHING AQUATIC SPECIMEN-OLD SCHOOL STYLE", we reproduced Anna Atkins method and celebrated her pioneering use of photography in sciencific records, achieving both aesthetical and functional purposes.
First step: Producing the cyanotype solutions
The cyanotype chemical procedures are very simple, and there are different formulas, with slight changes in the chemicals and its dosage. Our option was to produce two solutions as follows:
First solution-dilute 25g of ferric ammonium citrate (green) in 60 ml of water, then fill up to 100 ml with water;
Second solution- dilute 10g of potassium ferricyanide in 60 ml of water, then fill up to 100 ml with water.
Attention: Ferric ammoniacal citrate has two forms, green and brown. The green one delivers better results.
Second step: Paper sensitization
Mix equal volumes of the two solutions and, with a brush, apply directly to the paper.
Paper sensitization does not need to be done in the dark. A 40w incandescent light bulb about three meters away will do no harm. On the other hand, never use fluorescent lamps or try to sensitize the paper during the day without being indoors with closed shutters or with closed opaque curtains. The mixture of the two solutions is sensitive to UV radiation.
Once the paper is sensitized, leave it in a dark place to dry. This paper should be used within 48 hours. After that time the natural oxidation of the solution will make its use impractical.
You can also use an hair dryer to speed up the drying time.
If you want to reuse the cyanotype mix, you must keep it inside a opaque container, and store it in a closed cabinet, safe from UV radiation.
Third step: exposure
As in all copy processes used throughout the 19th century, obtaining an image with the cyanotype procedure was done by direct contact of the negative with the paper.
In order to obtain better results we used, as Anna Atkins did, a sandwich made with two plates, one made of glass and the other made of a rigid material like wood, and between the plates we place the sensitized paper and specimens collected in our previuous day expedition.
This set was then exposed to the sun for the time needed for image formation.
the amount of time depends on the light conditions and this is where practice and common sense come in. The UV intensity varies depending on the season, the location, the time of day and the weather conditions, that is. On our sunny conditions, we where able to get a proper exposure (detectable when the sensitized paper changes its color from the original green to a greenish gray colour) .
Fourth step: Devolpment/fixation
This is quite simple in the cyanotype procedure.
We simply placed the paper in a plastic tray with running water until all excess of the sensitizing solution is washed, then just let it dry in the shade and it was it.
In two or three days, the images reached its definite blue tonality.