Correcting Tone and Exposure - Beginning Photo Retouching and Restoration Using GIMP - page 44

You can access the Sample Points dialog from the Image menu (Windows ➤ Dockable Dialogs ➤
Sample Points). To create a Sample Point, Control + Click on one of the rulers in the image window, and drag
with the mouse. Two perpendicular guides will appear. When you release the mouse button, the Sample
Point will be placed where the two guides intersect (Figure 3-8 ).
Figure 3-8. Creating a Sample Point
The Brightness-Contrast Dialog
This is the first tonal correction method that many beginners use. The Brightness-Contrast dialog (Figure 3-9 )
has two sliders: one for brightness and one for contrast. The adjustments are broad, with little ability to
fine-tune, so this method of contrast adjustment has limits. When overused, it obliterates image detail.