Choose Enhance > Adjust Lighting > Levels.
Choose Layers > New Adjustment Layer > Levels, or open an existing Levels adjustment layer.
When you open the Levels dialog box, you still have access to the scroll controls in the document window, the View menu, and to the Hand and Zoom tools by using keyboard shortcuts.
When you are printing on white paper, you can achieve a good highlight in an average-key image using RGB values of 244, 244, 244. An approximate grayscale equivalent is a 4% dot.
You can approximate these target values quickly by entering 96 in the Brightness (B) text box under the HSB section of the Color Picker.
With a low-key image, you might want to set the highlight to a lower value to avoid too much contrast. Experiment with Brightness values between 96 and 80.
The pixel values throughout the image are adjusted proportionately to the new highlight values. Any pixels lighter than the area you clicked become specular white. The Info palette shows the values both before and after the color adjustment.
When you’re printing on white paper, you can achieve a good shadow in an average-key image by using RGB values of 10, 10, 10. An approximate grayscale equivalent is a 96% dot.
You can approximate these same values quickly by entering 4 in the Brightness (B) text box under the HSB section of the Color Picker.
With a high-key image, you might want to set the shadow to a higher value to maintain detail in the highlights. Experiment with Brightness values between 4 and 20.