Cyanotype Reducing Process
The blue color of a fully developed cyanotype will be lightened in the reducing process. Although there are a number of household items that can be used to leach the color from a cyanotype, washing soda is the preferred agent and can be purchased in any grocery store’s laundry aisle. Before starting the reducing process, the print must be aged at least 24 hours to allow the emulsion to harden. In addition, it’s always a good idea to test the strength of the reducing solution by cutting an imperfect print into strips and submerging them for different lengths of time.
Step 1: Submerge print in distilled water for 2–3 minutes to completely saturate paper’s fibers and make them uniformly receptive to reducing bath.
Step 2: While print is soaking, make reducing bath: Pour one liter of water and 1–2 teaspoons of washing soda into shallow pan and mix well; make sure powder is completely dissolved before adding print.
Step 3: Transfer print from water bath to reducing bath. If print immediately turns bright purple, solution is too strong.
Step 4: Keep an eye on print because it will fade quickly and continue to fade until reducing agent is completely rinsed away; it’s best to remove print early rather than late.
Step 5: Rinse print facedown in pan under running water for 2–5 minutes. Again, depending on strength of solution and time submerged, rinsing time will vary (Photo 6).