Final answer:
If the desired amount of lift is not achieved in hair coloring, changing the developer type might be needed. Developers with higher volume can increase the oxidation process, which is essential for lightening hair and achieving the desired color.
Step-by-step explanation:
When the desired amount of lift is not achieved using a single process color in hair coloring, a change in developer type (option d) might be required. The developer's role is to open the hair cuticle and allow the color to penetrate the shaft. If the lift is insufficient, a developer with a higher volume might be necessary to achieve the desired lightening effect. Using a developer with a higher volume can increase the oxidation process, thereby improving the lift. In hair coloring, the oxidation of 1,4-diaminobenzene derivative to the quinone state initiates the creation of the dye. A failure to achieve the desired color could be explained by the oxidation process not fully completing, which may be due to an inadequate developer. Switching to a different type may rectify this. If the desired amount of lift (color lightening) is not achieved using a single process color, a change in application technique may be required. This could involve adjusting the way the color is applied, such as using a different application method, altering the saturation, or modifying the processing conditions. The choice of developer type (option d) or processing time (options a and b) may also impact the color outcome, but a change in application technique is specifically mentioned in the context of achieving the desired lift.