Modify the duotone curve for a given ink, Specifying overprint colors, Adjust the display of overprint colors – Adobe Photoshop CC 2014 v.14.xx User Manual
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8. Click OK.
To apply a duotone effect to only part of an image, convert the duotone image to Multichannel mode—this converts the duotone curves to
spot channels. You can then erase part of the spot channel for areas that you want printed as standard grayscale.
Modify the duotone curve for a given ink
In a duotone image, each ink has a separate curve that specifies how the color is distributed across the shadows and highlights. This curve maps
each grayscale value in the original image to a specific ink percentage.
1. To preview any adjustments, select the Preview option in the Duotones Options dialog box.
2. Click the curve box next to the ink color box.
The default duotone curve, a straight diagonal line, indicates that the grayscale values in the original image map to an equal percentage of
ink. At this setting, a 50% midtone pixel is rendered with a 50% tint of the ink, a 100% shadow is rendered in 100% color, and so on.
3. Adjust the duotone curve for each ink by dragging a point on the graph or by entering values for the different ink percentages.
In the curve graph, the horizontal axis moves from highlights (at the left) to shadows (at the right). Ink density increases as you move up
the vertical axis. You can specify up to 13 points on the curve. When you specify two values along the curve, Photoshop calculates
intermediate values. As you adjust the curve, values are automatically entered in the percentage text boxes.
The value you enter in the text box indicates the percentage of the ink color used to represent the grayscale value in the original image.
For example, if you enter 70 in the 100% text box, a 70% tint of that ink color is used to print the 100% shadows.
4. Click Save in the Duotone Curve dialog box to save curves created with this dialog box.
5. Click Load to load these curves or curves created in the Curves dialog box, including curves created using the Arbitrary Map option.
You can use the Info panel to display ink percentages when you’re working with duotone images. Set the readout mode to Actual Color to
determine what ink percentages will be applied when the image is printed. These values reflect any changes you’ve entered in the Duotone
Curve dialog box.
Specifying overprint colors
Overprint colors are two unscreened inks printed on top of each other. For example, when you print a cyan ink over a yellow ink, the resulting
overprint color is green. The order in which inks are printed, as well as variations in the inks and paper, can significantly affect the final results.
To predict how colors will look when printed, use a printed sample of the overprinted inks and adjust your screen display accordingly. Keep in mind
that this adjustment affects only how the overprint colors appear on-screen, not when printed. Before adjusting these colors, make sure to calibrate
your monitor.
Adjust the display of overprint colors
1. Choose Image > Mode > Duotone.
2. Click Overprint Colors. The Overprint Colors dialog box shows how the combined inks will look when printed.
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