Van Dyke Brown - Processing The Printed Image

Processing The Printed Image

The image must now be washed, or cleared, in several changes of water to remove soluble iron and silver compounds. It is good practice to slightly acidify the wash water, as iron compounds are more soluble in acid. A pinch of citric acid, dab of vinegar or pineapple juice will do the trick. As the image soaks, white cloudy precipitate of silver chloride will appear from the reaction of silver nitrate with chlorine in the water. Continue to wash for a few changes of water after this cloudiness ceases to appear.

Fixing is best done with a weak, alkaline fixer of 5% sodium thiosulfate with a teaspoon of household ammonia per liter. The alkali slows the fixing process and prevents rapid bleaching of the image. Almost immediately, the tones of the image will change to a deep chocolate brown. Keep fixing until the whites appear clear; about 2 minutes, and finish with a second, clean fix if desired for thorough removal of salts that would fade the image. Use a fixer clearing bath of sodium sulfite to help remove residual fixer, and give the print an extended wash fitting the absorbency of the substrate, around 30-45 minutes for absorbent papers, or 5-10 minutes for gelatin sized tile or glass.

Air dry the print without heat. High heat will change the color of the print to more neutral and weaken the shadows.