Image-correction palettes

Six palettes in the image-correction tab can be used for image processing. Simply click the appropriate button to open the palette.

Image-correction tab

Unsharp mask

The unsharp mask sharpens edges in the image without affecting overall image contrast. This mask can be used with soft or slightly out-of-focus images. The effect of the unsharp mask is very subtle, but makes a significant improvement to the overall appearance of the image.

Click the unsharp-mask button in the image- correction tab to open the palette.

Drag the sliders or enter values in the text boxes to adjust the parameters of the mask. Click the reset button to restore the default settings.

The full effect of the unsharp mask cannot be evaluated in the prescan image. It can only be judged in the final scan.

Unsharp mask (p. 55)

Selective color (p. 62) Variation (p. 37)

Hue, saturation, and lightness (p. 63) Brightness, contrast, and color balance (p. 38)

Tone curve and histogram (p. 56)

Changes made on the palettes are reflected in the displayed image; the tab turns red (Windows) or an asterisk is displayed (Macintosh) to show image processing is applied to the image.

Click the close button in the top right corner of the palette to close it.

Amount: to adjust the contrast of the mask. If the value is too high, pixilation is apparent; the image becomes noticeably rough or grainy.

Radius: to increase the edge sharpness of the pix- els.

Threshold level: adjusted in integers between 0 and 255. The default setting is 2. If the difference between the surrounding pixels is greater than the threshold level, that pixel is recognized as a sharp subject pixel. When the level is set to 0, the whole image is corrected. The threshold level can separate smooth or even areas from edges and details to be sharpened.

Shadow protection level: to limit the sharp subject pixels in the shadows. The level can be adjusted in integers between 0 and 255. When the luminance level is greater than the shadow protection level, that pixel is recognized as a sharp pixel.

With mask

Original image

54

Advanced image processing

55