In most cases, both exposure and white balance can be selected together when the objective is to normalize another image or a set of images against a source image that contains, for example, a bright white area with detail (i.e., that's not clipped), a gray card or a skin tone under similar or mildly varying light on location.
When normalizing against a color patch on a reference chart under consistent lighting conditions where color accuracy is crucial, it may be beneficial to disable the exposure option.
Although the tool is intended to provide a baseline between images, you can also use the tool on the same image where possible.
RGB values chosen with the eyedropper (N) are available to all open Catalogs or Sessions, so you can, for example, select a color and brightness value in a Session and apply it to an image in a Catalog, and vice versa.
- Select the source image (e.g., one with a gray card taken under specific lighting conditions).
- Open the Color tool tab and go to the Normalize tool.
- Enable White Balance and Exposure by adding a check-mark to the corresponding box.
- Click on the Pick Normalize Color eyedropper (N) and select an area you want to match (e.g., a bright white area, a gray card, or a color patch on a reference chart).
- The Pick field is updated with the selected color and the corresponding RGB values are listed alongside for the selected color space. This is determined by the nominated ICC Profile in the selected Process Recipe.
- Select the destination image that is the one you want to make the correction to (ideally under similar or identical lighting).
- Select the Apply Normalization eyedropper or toggle between the pickers using (Alt+N) and click on the area in the image to apply the correction to (e.g., if both exposure and white balance are enabled, a neutral area with slight color cast or with exposure disabled, the subject you want to color match, etc.).
- The image will be updated in the Viewer with the adjustment(s) applied. If the result is unexpected, continue to re-apply the eyedropper to a more suitable area with a similar tone. The image will be updated with the new correction.