The tone curve has moveable anchor points located at either end, one in the shadows and another in the highlights. They enable you to set black and white points (remap the darkest and lightest values in the tonal range), similar to the Levels tool. Indeed, if the black and white points have been previously set using the Levels tool, it is not necessary to make adjustments to the anchor points.
- Go to the Exposure tool tab.
- In the Curve tool, position the cursor on one of the anchor points – a guideline will be displayed to help with the positioning.
- Click and hold the anchor point and then drag it to the desired position. For example, to remap the tonal range, move the anchor points inwards horizontally so that the guidelines just touch the edge of the histogram.
- Repeat the procedure with the second anchor point.