As discussed earlier, sharpening increases contrast along edges. The four key sharpening tools in Photoshop – Unsharp Mask, Smart Sharpen, High Pass and the Detail Panel in Camera Raw – all have a Radius control. This determines how far from the edge sharpening will occur. Set to a low value, the contrast change may only spread a pixel or two from the edge, but with a higher value the change expands outwards on either side of the edge. If we push it too far, we might see halos around details in the image. As such, Amount and Radius are directly tied to one another, and one doesn’t work without the other.…