Photography Tips

Technique two: Unsharp mask/Smart Sharpen
The second technique is a continuation of the first technique and is intended to address the issues of increased saturation leading to the effect of color fringing. If a merged layer is used as the sharpening layer and this layer is then changed to Luminosity blend mode the effects of saturation are removed from the contrast equation. This second technique looks how the benefits of localized sharpening and Luminosity sharpening can be combined.

Step 1
Change the Blend mode of the High Pass layer back to Normal mode. Then apply a Threshold adjustment to the High Pass layer. Go to Image > Adjustments > Threshold.



Choose Normal from the blend modes menu in the Layers palette.



Choose Image > Adjustments > Threshold to apply a Threshold adjustment to the layer.

Step 2
Drag the slider just below the histogram to isolate the edges that require sharpening. The aim of moving these sliders is to render all of those areas you do not want to sharpen white. Select 'OK' when you are done. Paint out any areas that were not rendered white by the Threshold adjustment that you do not what to be sharpened, e.g. in the portrait used in this example any pixels remaining in the skin away from the eyes mouth and nose were painted over using the paintbrush tool with white selected as the foreground color.



Drag the histogram slider to isolate the edges that require sharpening.



Remaining pixels in the skin away from the eyes mouth and nose were painted over using the paintbrush tool with white selected as the foreground color.

Step 3
Go to the Channels palette and either Ctrl-click (Windows) or Command-click (Mac OS) the RGB thumbnail or click on the 'Load channel as selection' icon from the base of the channels palette to load the edge detail as a selection. Return to the layers palette and drag the Background layer to the new layer icon to make a background copy layer. Drag this background copy layer to the top of the layers stack.



Drag the Background layer to the New Layer icon to duplicate it.



Drag the background copy layer to the top of the layers stack.

Step 4
Switch off the visibility of the High Pass layer. Hold down the Alt or Option key and click on the 'Add layer mask' icon in the layers palette. Make sure the layer mask thumbnail is the active part of the layer and then go to Filter > Blur > Gaussian Blur. Apply a 1.5 pixel radius blue to the mask.



Switch off visibility for the High Pass layer and add a layer mask.



Apply a 1.5 pixel radius blue in the Gaussian Blur dialog box.

Step 5
Now click on the image thumbnail on the background copy layer. Ensure the image is zoomed in to 100% for a small image or 50% for a larger print resolution image (200ppi - 300ppi). Go to Filter > Sharpen > Smart Sharpen or Unsharp Mask. Adjust the Amount slider to between 80 and 150%. This controls how much darker or lighter the pixels at the edges are rendered. Choose an amount slightly more than looks comfortable on screen if the image is destined for print rather than screen.

Note: See Capture and Enhance for basic settings of the Unsharp Mask filter. The exact Threshold and Radius settings are not so critical for this advanced technique.



Adjust the values in the Unsharp Mask dialog box.

Step 6
Change the blend mode of the sharpening layer (the uppermost layer) to Luminosity mode. Luminosity mode will restrict the contrast changes to brightness only, and will remove any changes in saturation that have occurred due to the use of the Unsharp Mask. The changes are often very subtle so this technique is only recommended when you become aware of the problems of color fringing due to increased saturation.



If you become aware of the problems of color fringing, change the blend mode of the sharpening layer to Luminosity mode.

The illustration below is a magnified view of the effects of changing the blend to Luminosity. These two cutting edge techniques are capable of producing razor sharp images that will really put the finishing touches to a folio quality image.



Before and after the Luminosity mode change.