One of the most annoying things about underwater photography is when a great picture is ruined by backscatter. This can lead to an age in Photoshop trying to use the clone brush to remove each particle individually.
The dust and scratches tool at first glance looks like an ideal solution for removing white particles on a background (backscatter). However this has the effect of softening the whole picture.
However there is a method of using this filter to radically speed up the backscatter removal process.
The first step is to apply the dust and scratches filter to your picture. Apply it strongly and do not worry about the softening effect on the foreground. Make sure that all of the particles are removed by the filter.
In the History palette revert back to the original picture directly before the application of the filter. Switch to the history brush and ensure that the source for the history brush is set as the state after the dust and scratches filter (The history must be set to non-linear in the history options). Set the mode for the history brush to darken.
Now using a suitable brush paint over the backscatter. The light particles will disappear leaving the dark information intact.
This should be a far quicker process than using the clone brush and should also maintain the grain of the picture and the detail around the backscatter.
This technique should work in any image editor that has a history brush
If the above isn't clear please post any questions.
Mark