Modifying the duotone curve

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.

To modify the duotone curve for a given ink:

1. To preview any adjustments, select the Preview option.
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 prints with a 50% tint of the ink, a 100% shadow is printed 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, Adobe Photoshop calculates intermediate values. As you adjust the curve, values are automatically entered in the percentage text boxes.
• In the text box, the value you enter indicates the percentage of the ink color that will be 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 will be used to print the 100% shadow areas of the image. (See Using the Curves dialog box (Photoshop).)
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. (See Saving and loading duotone settings.)

You can use the Info palette to display ink percentages when you're working with duotone images. Set the readout mode to Actual Color to see the ink percentages that will be applied when the image is printed. These values reflect any changes you've entered in the Duotone Curve dialog box.