When you create custom layer styles, you can use contours to control the shape of Drop Shadow, Inner Shadow, Inner Glow, Outer Glow, Bevel and Emboss, and Satin effects over a given range. For example, a Linear contour on a Drop Shadow causes the opacity to drop off in a linear transition. Use a Custom contour to create a unique shadow transition.
You can select, reset, delete, or change the preview of contours in the Contour pop‑up palette and Preset Manager.