How to work with Gamma Correction
To work with Gamma Correction
Select the Choose Color tab from the Menu Bar and choose Adjust in the Menu. After that click Gamma Correction.
To adjust the red, green, and blue curves individually, clear the Link check box. By default, the sliders are linked so that they move in unison.
To update the original image automatically each time you change the settings, click the Auto Proof button.
The graph to the right of the sliders shows the curves for the three colors. The left side of the graph represents the shadows of the image; the right side represents the highlights. To view the image’s current settings, move the sliders to a setting of 1.00. The three curves will combine into a single straight line. This line mirrors the slider values in the Highlight/Mid-tone/Shadow dialog box, where the current image settings are 0% Shadow, 50% Mid-tone, and 100% highlight.
If the sliders are linked, drag any slider or type a number into any box to move the curve. Dragging to the right pushes more pixels into a higher lightness value and lightens the image. Dragging to the left darkens the image.
To change the color balance of the image, clear the Link check box and adjust the sliders individually. Drag to the right to add more of the color and to the left to remove it.
If you are not using the Auto Proof feature, click the Proof button to see the effect applied to the original image.