Adjusting Selected Colour
                  Areas Using Masks


After performing the Overall Colour Correction, the next step is to find the isolated parts of the image that can be improved even more, but will require a selection or mask to improve those areas. In this step we are going to enhance the look of the clouds.

Make sure that the active layer in the layers palette is the topmost. The active layer is the one that is highlighted; you can click the name of a layer to highlight it.

Choose Layer/NewAdjustment Layer/Curves, name it DarkenClouds.
Click a point in the center of the diagonal line and drag it down and to the right until the clouds have more drama and you like the way they look. Don’t worry about the rest of the image looking too dark, just get the clouds to look the way you want them.

Choose OK to finish your curve adjustment.

Notice that this DarkenClouds adjustment layer in the Layers palette has two thumbnails associated with it. The leftmost one is the Layer thumbnail and it contains the little icon that looks like a curve diagram, which shows you that this is a Curve type adjustment layer.
The rightmost thumbnail is the Layer Mask thumbnail and it is completely white, which means that right now this adjustment is happening on the entire image.

Choose Image/Adjustment/Invert to invert this Layer Mask thumbnail, and the layer mask to completely black. Now this curve change does not apply to any of the image.
Type a B to switch to the Paintbrush tool and select a 200-pixel (depending on the size of the area you want to paint).
Type a D for Default colours, which will make your foreground colour white and your background colour black. Make sure the Opacity and Flow are set at 100%. Now paint over the entire area of the clouds with this soft brush. Notice that as you paint, the darken curve is again applied to the areas where you painted in the mask with white.

If you accidentally go over the line, (in my example over to the mountain), and they get darkened, you can use Command-Z to undo the last brush stroke. You can also type X to switch the background to colour to black. Painting over the mountains with black will again remove the curve adjustment from the black painted areas.