PROCESSING PROBLEMS AND CAUSES

Processing                                                    Effect on Photograph
Solution                         Function                       Characteristics

FIRST          * Black and white negative images are            Speed, Contrast,
DEVELOPER        formed through the reduction of exposed        Colour Balance.
                 silver halide.  Requires the most care         Maximum & Minimum
                 among all processing steps in establish-       Density.
                 -ing conditions and in control.

FIRST WASH     * Stops activation of the First Developer.       Speed,
                 Also, prevents carry-over of the First         Colour Balance.
                 Developer into the Reversal Bath.

REVERSAL       * Fogging effects the residual silver            Entire density.
BATH             halide chemically which is not reduced
                 by the First Developer.

COLOUR         * When the silver halide fogged in the           Colour Balance,
DEVELOPER        Reversal Bath is reduced to metallic           Contrast, Maximum
                 silver through the action of the Colour        & Minimum
                 Developer, the oxidized colour develop-        Density.
                 -ing agents are reduced, and through the
                 coupling of this and the coupler within
                 the emulsion layer,for the colour dye.

CONDITIONER    * This acts as an accelerator for the            Minimum Density
                 following bleaching process in which
                 the metallic silver formed by the First                            
                 Developer and during Colour developer are
                 formed into silver halide. This process also
                 serves to prevent the pH from increasing due
                 to carry-over of the Colour Developer into
                 the Bleach by the film.

BLEACH         * The metallic silver formed by the First        Cloudy Colour.
                 Developer and during Colour Developer          Maximum & Minimum
                 are changed into silver halide.  In            Density
                 addition, the colloidal silver in the
                 yellow filter layer and the antihalation                           
                 layer is also changed into silver halide.

FIXER          * The silver halide formed during the            Cloudy Colour,
                 bleaching process is removed in the form       Minimum Density     
                 of soluble silver salts.

FIRST WASH     * Solution silver salts are removed from         Dye Stability
                 the film and the image is stabilised.
                 Also prevents exhaustion of the stabiliser
                 due to contamination with Fixer.

STABILISER     * Increases dye stability and prevents           Dye Stability
                 uneven drying.                                 Uneven drying.