Question

In coloured photography, the colour film is developed by oxidation of the developer and then reacting with:

• A. an alkai to form a salt
• B. a coupler to form a dye
• C. an acid to form a salt
• D. a metal to form a pigment

Answer 1

Answer: (B)

a coupler to form a dye

The development step uses reducing chemicals, and the exposed silver-halide grains develop to pure silver. The oxidized developer is produced in this reaction, and the oxidized developer reacts with chemicals called couplers in each of the image-forming layers. This reaction causes the coupler to form a color, and this color varies depending on how the silver-halide grains were spectrally sensitized. A different color-forming coupler is used in the red, green, and blue sensitive layers. The latent image in the different layers forms a different colored dye when the film is developed.