A method for preserving detail when adjusting tone scale of a digital image channel, the method comprises receiving a digital image channel; providing a tone scale function for adjusting the tone scale of the digital image channel; spatial filtering the digital image with a spatial filter which varies with location in the digital image channel according to the control signal producing a space-variant spatial filtered version of the digital image channel; using the tone scale function and the space-variant spatial filtered version of the digital image channel to produce an enhanced digital image channel.
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