Final answer:
The value that determines the scale size for corrections after using the Shadow/Highlight command to correct an underexposed image is the highlight value.
Step-by-step explanation:
The value that determines the scale size for corrections after using the Shadow/Highlight command to correct an underexposed image is the highlight value.
When using the Shadow/Highlight command, you have the option to adjust the highlight value, which determines the range of brightness values in the highlights of the image. Increasing the highlight value will expand the scale size for corrections in the highlights, while decreasing it will narrow the scale size.
For example, if you have an underexposed image with important details in the highlights that you want to bring out, you can increase the highlight value to expand the scale size and make adjustments to improve the brightness and details in the highlights.