[reference] Cyanotype paper test

After building the UV Box, and ordering the necessary chemicals, I decided to start my first cyanotyping project.

First I gathered a few types of paper I had lying around and suspected to be suitable to be drowned in water. I covered them with a stripe of cyanotype emulsion. On another spot, I applied a second layer of emulsion, to see if it makes a difference for the strength of blue color later.

After letting everything dry, I put the paper pieces in the UV Box and exposed them for 10 minutes with crispy UV light, then washed them in a tray of water and let them dry.

The papers I tested are:

Tosa Shi washi paper	Fabriano Artistico watercolor paper (cotton)
I LOVE ART watercolor paper (cellulose)	Canson „C“ a grain sketching paper 180 gsm
Kraft paper 80 gsm	Fabriano Ingres 90 gsm
Fabriano Disegno 5 watercolor paper (50% cotton)	LANA Colours Mixed Media paper

I really liked the result of the three papers in the upper right. Especially the Canson and the ingress paper. But it was really reassuring to see, that most paper I have would work for creating cyanotypes. Just the washi seems not to be suitable at all. Also, all papers survived the process of washing. Here the watercolor papers performed best, of cause.

I also liked the grain of the Fabriano Disegno 5, but for some reason it seemed like the emulsion was not penetrating it well, and a lot washed off, when I ranse the paper.

After I selected my two preferred papers, I wanted to check the influence of exposure time. For this I printed a few test stripes of a left over sheet of screen print films, that I still had.

Then I coated stripes of Ingres and sketching with a single coat of emulsion (since a double coating didn’t seem to have a big impact), and let them dry. I then exposed the stripes to UV light for 2, 4, 6 and 8 minutes to see which time results the best image.

Below 6 minutes there was no good result, at 2 minutes even no prussian blue was formed at all, the emulsion stayed water soluble and just washed off completely. 6 and 8 minutes of exposure time made a difference in values, but not so much in contrast, it seemed. For the canson paper the differences in values between 6 and 8 minutes where much stronger, that on the ingres paper.

A black value of 60% (fourth rectangle from the top right) seemed to be dark enough to block all light to the paper already. To see how much contrast I could get, I repeated the experiment with a test stripe with black values between 0 and 60%, in 10% and in a continuous gradient.

To make my life easier I used 6 and 8 minutes of exposure time since below 6 minutes the results were not looking nice anyways. I also added 10 minutes of exposure, since at least for the canson paper it seems like the maximum value of the prussian blue is not reached yet.

The second test confirms that black values of 60% are sufficient to create a white value on the cyanotype, for the exposure times I used. Only on the ingress paper there is a light shading after 10 minutes (Number 60 slightly visible on upper left rectangle). It appears that the canson paper needs a bit longer exposure time to create the same values as the ingres paper. Also, it appears like the canson paper has a higher resolution, value wise (on ingres paper after 8 minutes 0-20% rectangles appear to have the same value, after 10 minutes 10-30% appear to have the same value, while on the canson paper each block is distinguishable from the other).

The closest exposure time seem to be 8 minutes for the ingres paper and 10 minutes for the canson sketching paper.

Finally I used the gathered information for creating my first motive.

For the template I desaturated the original meme, inverted the values, put the background to about 70% black value and raised the contrast a bit, in the brightness/contrast setting of GIMP. Then I printed it on the same screen printing film, as the test stripes before.

I am quite happy with the final results. Especially on the ingres paper the values are copied in a nice way, of I might say so myself.

In future I want to try the Fabriano Disegno paper again and in another project, to try to find cheaper material (paper and for template) and methods (sun exposure [probably have to wait a few months for this], cutouts as template). I hope soon I can share more experiments with cyanotypes.