Washing film and paper

When washing film and paper, it is imperative that you wash out as much of the fix and development by-products as possible. Inadequate washing causes staining with age and lowers the archival quality of the photographs and negatives. Do not cut corners at this stage of your work!

A running water bath can be used for really effective washing of films and paper. With film, ensure the water is at 20C (plus or minus two degrees) but for paper, cold water is quite acceptable. 

The running water should be exchanging the old water for fresh water at a minimum rate of 12 times per hour. This is usually no problem for films as we tend to wash them in their processing tanks where the rate of water flow is high. Papers however, need a large tank or sink and this minimum flow is essential to fully rinse the emulsion of impurities.

We can test the flow rate by introducing a harmless dye into our wash water and timing how long it takes to clear. It should clear in less than 5 minutes. Potassium Permanganate solution is often used for the dye. Hypo testers check for any residual fix and show the effectiveness of the wash. I have included one here. If you prefer, films can be washed thoroughly and conveniently using the Ilford inversion method below...