Soft Proofing and Correcting Out Of Gamut Colors

Use a Hue/Saturation adjustment layer to correct out of gamut colors

 

Soft proofing is previewing, on a monitor, how your image's colors (or shades of gray if a black and white image) will look when reproduced by another device, such as a printer.  While proofing, you may or may not encounter out of gamut colors.

An out of gamut color is any color that cannot be reproduced by the targeted device.  For example, the image file may have a shade of cyan that renders fine on a monitor, but is unable to be reproduced exactly by a printer.  The color is in gamut for the monitor but out of gamut for the printer.  In order to bring the color in gamut for the printer, the color must be changed.  The objective is to change the color, and only that color, as little as possible.

 

Soft Proof

To soft proof an image for a printer, follow these steps.

1. Click View > Proof Setup > Custom.
2. Select the printer profile to be used by the print engine to print the image.
3. Set the rendering intent.  It is usually Relative Colorimetric or Perceptual.  For more information on rendering intent, read the Photoshop Color Settings page.
4. Make sure Use Black Point Compensation is checked.
5. Set Simulate.  Usually it is Paper White.
6. Click OK.  This establishes the profile to which the image will be proofed against.
7. Click View > Proof Colors.  This will allow Photoshop to try and display on the monitor what the image will look like when printed using the profile identified in the previous steps.

Use Ctrl + y (Command + y) to toggle between proofed and non-proofed views
 

Show Out Of Gamut Colors

When checking for out of gamut colors using a printer profile, be sure to use the profile for the printer/paper/ink combination that will be used to print the image.  Also remember, because different printer/paper/ink combinations will render an image differently, a color may be in gamut for one combination and out of gamut for another.  Therefore, check for out of gamut colors for each combination to be used.

1. If needed, establish the proper printer profile to be used to check for out of gamut colors. These steps are described under Soft Proof above.
2. Click View > Gamut Warning.

Any out of gamut colors will be displayed in the color defined in your Photoshop preferences.  To set this color, click Edit > Preferences > Transparency and Gamut.

In Figure 1, magenta is used to show out of gamut areas.  To fix out of gamut colors, follow the instructions below.

 

Fix Out Of Gamut Colors

1. First, make sure the gamut warning color is visible.  If it is not, click Shift + Ctrl + y (Shift + Command + y) to make it visible.
2. Click Select > Color Range.
3. In the Select drop down box, choose Out of Gamut.
4. Click OK.  This will create an active selection around the out of gamut colors.
5. Create a Hue/Saturation adjustment layer by clicking Layer > New Adjustment Layer.  Or, by clicking the Create New Fill or Adjustment layer icon at the bottom of the Layers palette.  The selection will become a layer mask.
6. In the Hue/Saturation dialog box, start by clicking in the Lightness text box.  Use the up/down arrow keys and slowly change Lightness until the gamut warning color disappears.  Be sure to try both increasing and decreasing Lightness.  Make a note how much Lightness had to be changed to bring the colors in gamut.  Note both how much it had to be increased and how much it had to be decreased.  Change the Lightness value back to zero.
7. Now repeat using the Saturation text box.  Note how much Saturation had to be changed to bring the colors in gamut.  Again, try both increasing and decreasing saturation.  Set Saturation back to zero.
8. Repeat for the Hue text box.  Set Hue back to zero.
9. You should now have six numbers: three positive and three negative.  Two for lightness, two for saturation and two for hue.  Using this information, decide which characteristic you are willing to change and make the change.  Usually, it is the one where the least amount of change brought the colors in gamut.  You only need to change one of the three characteristics.
10. Click OK to close the Hue/Saturation dialog box.  Leave blending mode Normal.

Because different printer/paper/ink combinations will render an image differently, you may find you need a different Hue/Saturation adjustment layer to correct out of gamut colors for each combination.  Do not try and force one adjustment to fix all the out of gamut colors for all combinations of printer/paper/ink.