CertiPort Practice Exam 2025 - Free CertiPort Practice Questions and Study Guide.

The process to destructively change the background layer saturation to -70 precisely involves adjusting the saturation levels using the Hue/Saturation controls within the image editing software. By navigating to Image > Hue/Saturation, you can change the saturation slider to -70, which directly alters the intensity of all colors in your image. This is a selective adjustment that specifically targets the color saturation, making it the appropriate method for achieving the desired effect on the background layer.

The other options either do not affect saturation directly or change different aspects of the image. For instance, adjusting exposure alters the brightness and contrast of the image rather than saturation. The Brightness command changes how light or dark an image appears, which also does not correspond to saturation adjustments. Lastly, modifying the contrast settings impacts the difference between light and dark areas, leaving color intensity unaddressed. Therefore, the Hue/Saturation adjustment is the most effective and relevant choice for the specified goal.