Nikon 4 user manual Unsharp Mask

Enhancing Images

3 Create an Unsharp Mask

Unsharp Mask can be applied to all the colors in the image or selectively to any combi- nation of red, green, and blue channels. Select a combination of colors from the Color pop-up menu. The Unsharp Mask you create will be applied only to edges in the selected colors.

4 Select values for intensity, halo width, and threshold

Intensity: The amount the contrast of edges will be increased. Too great an intensity will degrade your image rather than sharpening it.

Halo Width: The size of the areas that will be affected. The greater the halo width, the wider the edges in the sharpened image will appear. Too large a value for halo width will produce a “halo” along edges in the image.

Threshold: The limit at which sharpening will be applied. If the threshold is zero, sharpen- ing will apply to all pixels in the image. Increasing the threshold increases the amount of contrast that must be present between pixels before Unsharp Mask will be applied, with the result that only more distinctly contrasting edges will be affected.

5 Create additional masks

The controls in the Unsharp Mask palette allow you to select multiple combinations of colors that can be sharpened to different degrees. Repeat steps 1–4 to create additional masks for different color combinations. As new masks are created, they will be added to the end of the Unsharp Mask list. Masks apply in the order listed. To change the order in which masks apply, select a mask in the Unsharp Mask list and click the up arrow to move it up in the list, or the down arrow to move it down. To delete an Unsharp Mask from the list, select it and click the Delete button.

Unsharp Mask

Unsharp Mask sharpens edges without affecting color balance by making adjustments only to luminosity (brightness). The effect is the same as performing Unsharp Mask with the Luminosity channel selected in the Adobe Photoshop Lab color model. If Unsharp Mask is applied to a single channel, such as red, the values for ab (chrominance) are used to determine what points in the image are red, and Unsharp Masking applied to the Luminosity channel for those points only. An intensity of around 20% in Nikon Capture 4 is roughly equivalent to 100% in Adobe Photoshop.

No sharpening will be applied if Intensity is set to zero. Intensity must be set to at least 1% if sharpening is to apply.

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