Jim Patterson's cyanotype for you cyano techies
Below is Jim Patterson's cyanotype method. I share it for those who experience a lot of bleeding, etc. I use the 20 FAC/8 pot ferri formula which works great for me (with a good curve) with no bleeding and overexposure but I remember some people complaining about bleeding so thought I would share this. Let's put it this way--it is like a Rex formula but doesn't cost $29...
(Please reference Jim when using this formula)
Attached is my version. It sounds like Cyanotype Rex, but T. King never reveals all the details on line and I wasn't going to pay for his disc. I probably did something wrong in traditional Cyano with ferric ammonium citrate and potassium ferricyanide sensitizer. I got staining, bleeding, and blue wash water. The prints dripped blue water while drying on the clothes pins. The exposure is so much faster than the traditional formula that at first you don't believe it. It may not be any better than yours or others who get good prints with Cyano.
CYANOTYPE: Stop the Bleeding by Jim Patterson 10-2007
I never liked Cyanotype due to the bleeding, staining, blue wash water with the image seeming to wash away. (Overexposure was the remedy) I probably did something wrong. I read some articles by Mike Ware and Terry King, old photo texts, and experimented.
SENSITIZER: 100 ml distilled water
10 grams ferric oxalate
Slow to dissolve, stir occassionally, may take several hours or overnight.
CONTRAST AGENT: Use ammonium dichromate drops if needed to shorten the scale.
Coat paper, dry (fan, no heat), and expose in print frame to UV light. Fast exposure; my unit of eight 18-inch blacklight tubes from Home Depot about 3 inches from the print frame needs only 1 minute exposure. Overexposure is not needed in this process as there is almost no loss of image on developing and washing.
DEVELOPER: Final concentrations are 1.5% ferric alum, 1% potassium ferricyanide, and 25 % ammonium sulfate in distilled water. This solution slowly decomposes after mixing; thus, the 2 part stable stock solutions mixed just before use.
SOLUTION A: 950 ml distilled water
15 grams ferric ammonium sulfate, dodecahydrate (ferric alum)
(FeNH4(SO4)2. 12 H2O)
250 grams ammonium sulfate ((NH4)2SO4)
SOLUTION B: 50 ml distilled water
10 grams potassium ferricyanide (K3Fe(CN)6)
WORKING SOLUTION: 19 parts A : 1 part B (e.g. 190 ml A + 10 ml B)
Immerse the exposed paper face up in the WORKING SOLUTION in one smooth move and agitate the tray for 3-5 minutes until fully toned to the maximum dark blue. Wash in 2-3 tray washes of 0.5 % acetic acid (1part white distilled vinegar: 9 parts water) until highlights are clear and water is clear. The surface is very delicate. Don't touch the image area until dry. Develop and wash only one print in a tray at a time face up. Dry and marvel.
Christina Z. Anderson
Assistant Professor, Photo Option Coordinator
Montana State University, VCB 220
Bozeman Montana 59718