Here is a simple way to adjust exposure in f-stops, which is second nature for photographers. The key to this technique is that the screen and multiply layers of blend modes, with a coverage of 38%, an effect similar to lighter or darker by a full f-stop. (For the adjustments of half a point, with coverage of 19%% to use more than one-third 13, etc.). In this example, we're going to darken the image of a parade.
1.Create a correction of low f-stop.
If you are in a single file, duplicate the background layer by selecting Duplicate Layer from the Layer menu. If you are working on a file with layers, create a new layer by selecting New> Layer from the Layer menu, press Command-Option-Shift-E (Mac) or Ctrl-Alt-Shift-E (Windows) to merge the contents of all visible layers in the layer, while the lower intact.
2.Apply a global correction f-stop.
Select the newly created layer in the Layers palette, set the blending mode to Multiply and opacity to 38%. This image is dark overall with a plug.
3.Add a layer mask.
The overall picture is one of the vegetation along the water line into the dark. To return from the correction locally, you need a mask layer, adding a layer mask from the layer menu to add. In this case, using the Reveal All option, but select the option with the minimum of paint, if you want to correct a small area for the most efficient choice, enlarge any paint correction is needed, and instead choose to show all then paint correction.
Note that the layer mask automatically within the range of channels and new expertise and background colors are automatically set to black and white, ready for editing the layer mask.
to share with the foreground color to black, with the brush tool set to a soft brush on the correction in the areas where you do not want to paint. In this case, we have painted with a coverage of 33% for correction along the water line to reduce the third stop.
This technique is suitable for many variations. After the fix is part of the image is limited, can the intensity ranging from low to cover, for example, if you decide that you should have a fix for two stops, providing 38-76%% increase.
You can also experiment with different techniques to reduce the correction. If correct, the area or to protect the area that is easy to choose, you can make the selection of the mask layer, then use the selection or hide options, respectively. If you want to limit the definition to a specific range of colors, you can use Blend If to limit options in the dialog layer styles to suit the desired tone. For small local patches, you can set the History Brush from the spring to the current image, and how to brush set to multiply or screen using this method is especially useful for the corrections to the delicate brush set very low turbidity in three % to 10%.