When the Unsharp Mask is applied to the entire photograph, there is a possibility of color shifts, halos and other unforgiving results. Using this very easy technique will add more sharpness without leaving the nasty halos. Try it, it really works.
1. Open the file. Choose File --> Open --> Enter the image name to be fixed.
2. Choose Windows ---> Channels to display the channel palette.
3. Choose Image ---> Mode ---> Lab Color to display the photograph in lab color.
4. Click the channels tab and on the lightness channel. The photograph will now be in gray scale.
5. Choose Filter ---> Sharpen ---> Unsharpen Mask to display the Unsharp Mask settings. Start with Amount: 100% - Radius 1 pixel - Threshold 3 levels. Move each control to a preferred setting. Look in the preview window and click the plus+ button to enlarge the photograph. When you are content with the settings, click OK.
6. Choose Image ---> Mode ---> RGB Color to display the photograph in normal colors.
7. Choose Save As to save the file with a new name.