With the tools in iMovie you can adjust the image quality—including levels of black and white, exposure, brightness, contrast, saturation, and white point settings—of any video clip or photo you’ve added to a project.
If you change image quality in an Event (source video), the change is reflected in any future project to which you add the altered video.
To adjust image quality:
In the Project browser, double-click the video clip or photo you want to adjust, and then click Video at the top of the inspector that opens.
You can also select multiple clips to adjust at once.
The graph at the top of the Video Adjustments window, shown below, indicates the levels of red, blue, and green in the image’s shadows and highlights.
To have iMovie optimize the image’s levels, click Auto at the bottom of the inspector.
To create the effect you want, drag any of the following sliders:
Levels: Adjusts the black and white levels in the image. Dragging the left slider to the right increases black; dragging the right slider to the left increases white.
Exposure: Changes the shadows and highlights; dragging to the right intensifies the highlights.
Brightness: Changes the overall light level; dragging to the right makes the image lighter.
Contrast: Changes the relative contrast of light and dark tones; dragging to the right makes edges between light and dark areas more stark.
Saturation: Changes the color intensity. Dragging to the right makes the colors richer; dragging all the way to the left makes the image black and white.
Red Gain, Green Gain, and Blue Gain: Changes the amount of red, green, and blue coloring; dragging to the right increases the intensity of each color. (These sliders are visible only if you’ve turned on Advanced Tools.
White Point: Changes the color range by resetting the color white; click in the circle and drag around to maximize the white tones. Or, move your pointer over the image in the viewer; it changes to an eyedropper. Click a white or gray area in the image to reset the white point.
When you achieve the look you want, click Done.
If you change your mind about the changes you’ve made, you can undo your changes at any time by selecting the video clip or photo again and returning the sliders to their original positions. You can also restore the image to its original state by opening the inspector and clicking “Revert to Original” at any time, even after you’ve closed and reopened iMovie.