Correcting Tone and Exposure - Beginning Photo Retouching and Restoration Using GIMP - page 54

Tutorial 3: Using the Eyedroppers in Levels
Another method of improving contrast with Levels is using the Black and White Point eyedroppers These
tools are used to sample the darkest and lightest areas of the image, to remap tonality and improve contrast.
This image (Figure 3-20 ) has very low contrast and is extremely flat. It's difficult to know by visual
evaluation alone where the darkest and lightest range of pixels exists in this image. We will use the Threshold
feature to find the black and white points of this image. Threshold reduces the pixels to pure black and
white. It can be used to find where the darkest and lightest pixels exist in an image.

Figure 3-20. A very low-contrast image

To correct this image, follow these steps:

1. Open the image ( Ch3_lady with baby ) found in the Practice Images folder.

2. Duplicate the background layer three times (Shift + Control + D). Rename the

first duplicate layer Contrast Adjustment. Rename the other two layers Black
Point and White Point, respectively (Figure 3-21 ).