	Mike Ware Cyanotypes Caitlin Gilliam
Student Projects , Photography

Introduction:

For my final project I worked with an alternative photography processes, specifically the new cyanotype process developed by photographer Mike Ware. I varied the levels of citric acid in the sensitizer solution to discover how the acidity affected the print quality. I hypothesized that the higher acidity would increase the contrast in the print. I used the same acid free paper and negative for each print.

Background:

Cyantoypes, also known as blue prints, were developed in 1842 by Sir John Herschel. The old process uses ammonium iron(III) citrate, potassium ferricyanide and distilled water, and two sensitizer solutions. The new process uses a single solution of ammonium iron(III) oxalate ( rather than the citrate), potassium ferricyanide, and distilled water. It is a more expensive and more complicated process, but produces much higher quality prints. A 2% citric acid bath can be used rather than a water bath. This allows for better color retention in the print.

Procedure:

	1.Using a pestle and mortar, finely powder 10 g Potassium Ferricyanide. Wear a dust mask, to avoid inhalation of the powder, and pay attention to thoroughly completing this step, which is indicated when all the red crystals are crushed to a yellow powder.
	2.Heat ca. 30 cc distilled water to ca. 50 °C and dissolve in it 30 g Ammonium Iron(III) Oxalate.
	3.Add 0.5 cc 25% Ammonium Dichromate solution, (previously prepared by dissolving 5 g of the solid in distilled water and making up to a final volume of 20 cc). Mix thoroughly.
	4.To the solution, while it is still hot, add the 10 g of finely powdered Potassium Ferricyanide in small portions with vigorous stirring; few (or preferably no) red crystals should be seen, and green crystals will begin to appear. Set the solution aside in a dark place to cool and crystallise for about one hour.
	5.Separate most of the liquid from the green crystals by filtration. The green solid (Potassium Iron(III) Oxalate) is disposed of safely (poisonous!). The volume of solution extracted should be ca. 30 to 33 cc.
	6.Make up the olive-yellow colored solution with distilled water to a final volume of 100 cc.
	7.Filter the sensitizer solution and store it in a brown bottle kept in the dark; its shelf life should be at least a year.
	8. Coat one side of the first piece of paper with the sensitizer solution. Be careful not to leave puddles of the solution. The coat should be even. Let the paper dry completely.
	9. Once the paper has dried, place a 4x5 or Holga negative (35mm is too small) emulsion side down onto the paper. Place the paper, coated side down, on a UV light box.
	10. Expose the paper for 6 minutes. The image should appear on the paper. The darkest areas on the negative should appear lighter giving the image a solarized appearance.
	11. Soak the image in a 2% citric acid bath for 10 minutes, image side down.
	12. Soak the image in a water bath for 20 minutes.
	13. Take the paper out and let it dry for 24 hours.
	14. Reapeat steps 8-13, but first add 3 drops of a 20% citric acid solution to 20 ml of the sensitizer solution. Coat the 2nd sheet of paper with this solution
	15. Reapeat the process again. This time add 6 drops of the 20% citric acid solution to 20ml of sensitizer solution.

Observations and Data

Measurements:

Ammonium Iron (III) Oxalate (NH₄)₃[Fe(C₂0₄)₃]^.3H₂0	30.026g
Potassium Ferricyanide K₃[Fe(CN)₆]	10.00g
Ammonium Dichromate (NH₄)₂Cr₂0₇ (25% solution)	0.506g

Observations:

1. Grinding the Potassium Ferricyanide	The red crystals became a yellow-orange powder. Tedious, but easy to grind.
2. Heating the water	Be careful not to allow the water to boil because some volume will be lost in evaportion
3. Adding the Ammonium Dichromate	The color of the solution becomes darker and greener. May have a slightly brown hue.
4. Adding the Potassium Ferricyanide	Some orange clumps remained, but no red crystals. The solution became cloudy, and a lighter green.
5. Filtering	The clumps of orange and the green crystals remained in the filter paper. The green solution drained to a volume of 25.6 ml. It was clear and green.
6. Add water to equal 100 ml	The solution is less concentrated. This makes it more transparent.
7. Store in Bottle
8. Coating sheet #1	The solution without any citric acid is a pale yellow-green hue. It coats evenly and doesn't seem to destroy the texture of the paper. The coat is smooth after drying.
9. Place paper and negative in box	It is best to use art tape to keep tthe negative in place. A sheet of glass can be used to steady the paper and negative. This will also flatten the negative and paper out making for a clearer print.
10. Expose paper	At 6 minutes the paper becomes a dusty blue shade. The shadows in the negative become the lightest value on the print. It does look solarized.
11. Citric acid bath	Once in the citric acid, the dusty blue becomes a vibrant prussian blue hue. The citric acid bath begins to have a lime green hue. You can see the yellow leaving the paper.
12. Water bath	Any remaining yellow hue came out in this wash. The white of the paper is white again with no remains of the sensitizer solution.
13. Drying	The intense prussian blue dulls slightly with drying. It darkens also. It is now closer to an indigo, but still is prussian blue. Print #1 has a good contrast and the bottom scale shows a clear transition between values. There is a good range of values present within the print and on the scale.
14. Sheet #2 (3 drops)	When coating the paper the solution is a slightly greener hue. The value is the same. This print is slightly darker. It has greater contrast. The scale at the bottom shows some impurities in value. Perhaps the citric acid has caused damage to the paper fibers. Somehow it has created a less consistant, blotchy value scale.
15. Sheet #3 (6 drops)	After coating this sheet the hue seems even greener than the one before. The value is the same. This printer again has a slightly greater contrast. The white of the paper is whiter than the other prints. This could be because the bath cleansed it more effectively. The scale at the bottom shows even greater inconsistancies in value. The light tones have blue blotches where They should be clear.

Conclusions

The use of citric acid can benefit a print. Rinsing the prints in a 2% acid bath is crucial to preserving the color and intensity of the print. Adding the drops of 20% citric acid raised the contrast, but didn't imporve the overall quality of the print. With a rise in contrast there is a decrease in smooth value transition. This is not as evident in the prints as in the scales below the prints. It would be interesting to test further by making the sensitizer soltion more basic. The best print is the print using 3 drops of the 20% citric acid solution. It has a balance of contrast and value transition consistancy

Links

More information can be found at :

http://www.mikeware.demon.co.uk/cyano.html

http://www.alternativephotography.com/process_cyanotype2.html

Acknowledgements

Dr. John Bordley

Pradip Malde

Rachel Malde

Mike Ware Cyanotypes