Photoshop retouching Image (iv) adjusting gamut

Adjust color gamut

The gamut describes the number or detail of the image contrast, and determines the pixel distribution, from the darkest pixel (black) to the brightest pixel (white). We now use the levels command to correct the contrast of the photos.

1. Choose Image > Adjust > Levels to ensure that the Preview option is selected.
Notice the histogram in the dialog box. The triangle at the bottom of the histogram represents the shadow (the Black triangle), the highlight (the white triangle), the middle hue or the gamma (gray triangle). If the image has color throughout the brightness range, the graph will traverse the entire width of the histogram, from the black triangle to the white triangle. Instead, the graph gathers toward the center, showing no dark or bright colors. You can also adjust the monochrome black and white dots of the image to extend its tonal range.
2. Drag the triangle to the left and right to the center of the histogram (indicating the darkest and brightest color at the beginning). Click OK to determine.

Add Shadow (black triangle) highlight (white triangle) result

3. Choose Image > Histogram to see the new histogram. The tonal range now extends to the entire histogram. Click OK to determine.
4. Select File > Save to save files.