Washing Prints

After all the undeveloped silver halide has been removed, the emulsion is still saturated with the chemicals of the fixing bath and some dissolved silver compounds. If these are not removed by washing, staining may occur or the image may discolor and fade.
Time for complete washing

A complete wash is achieved in the shortest time when the material surfaces are exposed to a rapid flow of fresh water. Washing time is affected by the type and condition of the fuser bath, the design of the wash tank, and the temperature of the wash water.

Hypo is generally eliminated from most films in 20 to 30 minutes if the flow rate of water is sufficiently rapid to completely replace the water in the wash tank every 5 minutes.

Barite Paper

Barite paper prints should be washed under these conditions for at least 1 hour if the hypo is to be removed in an archive-safe manner. A brief rinse of each film or print before placing it in the wash tank greatly aids the washing process.

Papers require a longer wash time than films because small amounts of hypo are stubbornly held by the paper substrate and are difficult to remove by washing alone. A hypo clearing agent is a wash aid that allows faster and more complete washing of both films and prints, even with cold water, to achieve greater stability than can be achieved under normal processing conditions.

RC Paper

Wash RC papers for only 4 minutes. Do not put too many papers in the tray at the same time, or the prints will become matted, impeding water circulation and making thorough washing impossible. The Kodak automatic tray siphon is a convenient device for promoting efficient water circulation.

Water Temperature

Washing efficiency decreases rapidly with decreasing temperature and is very low at temperatures below 16°C.

For efficient washing, the water temperature should be between 18° and 21° C. If the water temperature is below 18° C, the wash time must be extended; if the water is very cold, even long wash times may not adequately remove the fixative. Water temperatures above 24° C should be avoided; warm water can soften and swell the emulsion, making the prints susceptible to physical damage and not noticeably reducing the time for thorough washing.

Removing fixative with washing aids

Various washing agents speed up the rate at which the hypo is removed from the paper, thus reducing the wash time for the prints. When using such a hypo-clearing agent, a 10-minute wash for single-weight prints or a 20-minute wash for double-weight prints is sufficient, even with water as cold as 2°C.