The last few months have been concentrated on improving my #altprocess printing skills, both Cyanotype and Kallitype. Cyanotype is by far the simplest of the two but it's also very easy to get it "wrong". With the definition of "wrong" varying wildly depending on what you are trying to achieve.
What I'm trying to achieve is high quality cyanotype photographic prints with as big a range of tones and graduations as I can achieve. I'm not doing anything new here, just pulling together from lots of sources of information and trying to make something work for me.
(The above image is by Dave Whenham. I made cyanotype and kallitype prints for him as part return for the huge favour of lending me his RB67 camera). 🙏
At it's most basic to make a cyanotype you coat a piece of art paper with sensitizer, place a translucent object over it, cover that with glass, expose it to UV light and then wash in water. Simples... This however doesn't give you the control of translating the tones in a negative to the required tones in the print. It doesn't allow you to control and place the deepest "blues" and brightest whites.
To do those things you need to calibrate. I use the Easy Digital Negatives process. It's reasonably simple and easy to follow and gives a great starting point for your printing.
There are however many things that can and will catch you out:
Coating issues, such as contaminated brushes, uneven coating technique or poor sensitizer absorption. I went through a whole pack of Hahnemuhle Platinum Rag trying to get prints that didn't wash out.
Weak "blues" due to bad calibration, incorrect exposure or old/bad paper.
Washing out of print by bad water. My East Anglian tap water is just terrible.
I think I've "nailed" my cyanotype process for now:
As good as I can get EDN calibrations for each paper
Bergger COT 320 or Arches Platine paper
2" Jackson's Icon Mottler brush for coating
1% Citric Acid first wash (2 mins)
0.3% Hydrogen Peroxide rinse (to check the blues)
Filtered or Dehumidifier water, circulated with a fish tank pump