The exercise below has to do with sharpening your files…1. Sharpen to De-Fog a file 2. High Pass sharpening and 3. Selective sharpening. What sharpening does is create more contrast between pixels which then gives the appearance of making an image seem sharper.
Below is the dialog box for the Unsharp Mask FIlter:
Amount: Controls the overall intensity of the sharpening.
Radius: Controls the extent of the pixels effected by the sharpening.
Threshold: Is the middle man…it basically backs off the effect in smooth tonal gradations like skies, skin, smooth backgrounds and smooth tones inside of textured areas. The bottom line is that this filter does increase noise…be careful.
Because this filter increases contrast you have to be very careful on how much you use. Too much will begin to create halos around edges where the effect occurs.
The amount of unsharp mask you use is dependent on the file size…smaller the file the less is needed and of courses the larger the file the more is needed. When working with this tool periodically view the image at 100% in order to monitor the effect.
Most digital images have a tendency to be flat because the chip has a large dynamic range. To help remove this overall haze a slight bit of unsharp mask clears it up.
Start with these settings for high res files:
Before and after Defog:
High Pass Sharpening
Sharpening is all about controlling the edges. The high pass filter works miracles. There’s really no magic here…it’s learn as you go in terms of what works for you.
1. Duplicate the background layer.
2. Run the high pass filter.
3. Change blending mode on the top layer to overlay.
Here’s our image before using the High Pass filter:
This is an ideal way to control what you want sharpened or just left as is…this is a great tool when dealing with large areas of texture and smooth graduated tones where you want maximum sharpness in texture and very little in smooth tones like skin for example. This can be accomplished by using the history palate and painting with the history brush or by using a mask and painting from one layer to another.
First I’ll duplicate the background layer. I’ll apply some unsharp mask to the second layer, attach a mask to the top layer and use a soft brush and black paint at an opacity of 50% to paint in the areas that I want to sharpen. I start at 50% opacity so I can slowly build up the effect, this gives me more control. When working with skin tone you want to leave the skin alone and just paint sharpening into the hair, eyelashes,teeth and eye brows.
The curves adjustment is just for overall tonality because sharpening changes contrast. The top layer is the straight image and the bottom layer is the sharpened layer.
This is the mask used to pull the sharpening from the bottom layer.