Today’s Question: I realize you can use soft proofing in Photoshop to see which colors in the image are out of gamut based on a particular printer profile. But is there then an easy way to select those out of gamut areas so an adjustment can be applied to only those areas, leaving all other pixels as they are?
Tim’s Quick Answer: You can actually select out of gamut colors very easily using the “Out of Gamut” sampling option available with the Color Range selection command.
More Detail: The Color Range command in Photoshop is generally used for creating a selection of a specific range of color values in an image, often to select a particular object or area within the photo. However, there are also additional sampling options available for the Color Range command, including an option to select out of gamut colors.
The first step is to configure soft proofing based on the desired output conditions. To do so, choose View > Proof Setup > Custom from the menu. In the Customize Proof Condition dialog that appears, set the applicable output profile using the “Device to Simulate” popup. Set the desired Rendering Intent (in most cases I recommend using “Relative Colorimetric”), and turn on the Black Point Compensation checkbox. Adjust any other settings as desired, and click the OK button to apply the change and enable the Proof Colors view option.
If you’d like to see a preview of which areas of the image are out of gamut, you can choose View > Gamut Warning from the menu. Then, to get started creating a selection of the out of gamut areas, you can choose Select > Color Range to bring up the Color Range dialog.
Within the Color Range dialog click the Select popup, and choose “Out of Gamut” from that popup. You can then click the OK button to close the Color Range dialog and create the selection of the out of gamut colors in the photo.
You can then, for example, add an adjustment layer to apply an adjustment to the selected out of gamut areas of the photo, or otherwise work specifically with that portion of the image.