Photographic negatives can be washed free of residual chemicals with relative ease whereas prints require much more controlled washing to eliminate residual fixer (hypo). This is necessary for modern photo-graphic paper and film as well as for stained and faded photographs. Methods of reprocessing contaminated films, plates and prints are de-scribed and the test for identifying nitrocellulose film (ignites spon-taneously) is given. As nitrocellulose film decomposes nitrogen dioxide, interacting with moisture in the air, forms gases which may damage other objects in the museum. References and formulas are provide.