"Curves" is the most powerful tonal adjustment tool in Photoshop. Although its functionality and work principles are very similar to those of "Levels", this method lets us edit virtually any tonal range, or even adjust several different ranges in different ways.
- In the Effects palette, double-click the "Curves" thumbnail. In the "New Layer" dialog, click "OK".
- Very carefully pull some middle point of the graph to brighten or darken the image midtones.
- Pull the graph at some lower point rightward to decrease brightness in the darker areas (let's say, in "mid-shadows").
- Uplift the upper segment to brighten the "mid-highlights" (screenshot).
- To define tonal range more precisely, [Ctrl]-click a specific spot on the image. Then pull the graph at the added point to adjust the selected range.
A dialog box will appear allowing you to adjust image tone by editing the graph. Generally speaking, the sharper your graph is the more contrasting the image will be.
Please note, though, that when unlocked in Photoshop Elements, this tool has 3 important restrictions:
- The command is only available as an adjustment layer. (To adjust only the current layer, check "Group With Previous Layer" in the "New Layer" dialog.)
- You can't re-edit the settings of the created adjustment layer.
- It hasn't "Channel" menu (i.e., you can't edit color channels separately).
