Tip about edges in painting! Edges are closely related to value. Notice here how the soft edge of the shadow on the sphere is simply a slow gradient of value. This slow change of value tells us that the sphere is round, but it also appears as an abstract shape with a soft edge.

If a soft edge is simply a slow gradient of value, then a hard edge is when there is a very fast change from one value to another. The more different these values, the harder the edge appears. The sharpen filter in photoshop works by accentuating this difference in value.

A lost edge is when the values between two objects appear the same. Take a look at where the value of the sphere in the light is the same as the background, this is a lost edge, along with where the value of the sphere in shadow merges into the cast shadow.

Can you spot all the relationships between edges and values in this painting by Walter Ernest Webster? I've labelled a few of them, try and see how the rest fit into the overall hierarchy, and how that contrast leads our eye.

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