Сyanotype - the most popular of the alternative photoprocesses, because of its simplicity, and a number of other advantages.
It is necessary to enumerate the advantages of the process:
- It’s one-stage process, after the exposure simply rinse the imprint of the remnants of unreacted reagents;
- Process does not require exact dosages of reagents;
- Reagents are cheap, accessible, stable, well kept, relatively safe;
- Sensitized paper can be stored in a dark place about a week;
- Low sensitivity makes it convenient treatment of sensitized paper, it can be removed and inserted into the frame for printing, even on the weak light of day, in addition, the low sensitivity makes undemanding to the accuracy of exposure;
- You can print on a variety of materials: fabric, paper, cardboard, wood;
- The resulting image is very stable;
- Possibly rendering images in different ways depending on the desired color.
Stage 1. Print negative.
You need to prepare a digital image to print and print it on transparency film (I use Lomond Inkjet Films) to get a negative.
*Open digital image in Photoshop;
*if you have color image, desaturate it (Image > Adjust > Desaturate);
- invert image in the negative (Ctrl+ I);
- set brightness and contract (Hue / Saturation). For cyanotype we need high-contrast image!!!
- flip the image horizontally (horizontal flip);
- expose resolution for printing (>=300 dpi);
- print image. You may do it yourself (no matter what kind of printer, inkjet or laser) or print in photo lab.
Remember, that we need big sized negative (A4) for A4 watercolor sheet of paper.
You can also use everyday objects like in doing photograms.
Stage 2. Formula.
- ferrotsitrata ammonia
- potassium ferrocyanide
- distilled water (if possible)
- 3 glasses (for storage and mixing solutions)
- brush to coat a paper.
Classic formula (rich dark-blue or blue):
25 grams ferrotsitrata ammonia per 100 ml of distilled water; solution A
10 grams of potassium ferrocyanide in 100 ml distilled water. solution B
Increasing concentrations of ammonium ferrotsitrata will move to the blue print tone, and the predominance of potassium ferrocyanide gives a dark blue tone.
Here is another recipe that gives a dark blue color:
27 grams ferrotsitrata ammonia per 100 ml of dist. water;
23 grams of potassium ferrocyanide in 100 ml of dist. water.
Dissolve the chemicals in water to make two separate solutions. To prepare solutions we need weigh the necessary amount of reagents and pour in the tank for mixing. Then we pour into flask, filtering through coffee filters. (Ready-made solutions can be stored long enough in a dark and cool place).
Mix equal quantities of each solution together in a third container. This solution is finite.
We can prepare the solution A and B in the dim light, but we mix of these solutions and coat a paper in the dark (it is desirable, although a weak light is possible).
Also you can buy ready solutions, for example, Bostick & Sullivan (Cyanotype Printing Kit, $26,95).
Stage 3. Cover the paper.
Paper should be: 100% cotton, tight (!!! It’s important, because result will be soaked for a long time ).
Watercolor paper is the best choice.
Paper selection is important, and it determines the outcome, different contrast.
When choice of paper is done, paint the chemicals onto the material. You can cover sheet with two layers to give more richness of result.
Then leave a paper to dry in dark room for 1 hour.
Stage 4. Exposing and Soaking.
Place your negative in contact with your coated paper, with glass on the negative and a piece of cardboard under the paper. Like sandwich. It would be our frame for printing.
This sandwich can be exposed by natural sunlight (or UV light): ≈ 20 min. (sunny day), ≈ few hours (cloudy day).
Then you need rinse paper in cold water (≈ 20 min.) for removing unexposed chemicals.
Our print can be hung to dry (≈ 1 hour.).
You must remember, that:
*you can use not only the watercolor paper as a surface, but also cotton, wood or other material with good absorbency.
*experiment not only with negatives, you can use any of the surrounding objects for exposing, simulating the photogramm technics.
*don’t be afraid to experiment with the proportions of reagents, even slightly altering the weight, you can affect the shade of the final print.