VBA: get a color value

The code below produces a "Compile error: Object required" on line Set value = color.ToString  

ToString returns a String so is not a String an Object?
Thus why there is an error there?

Dim s As Shape

Dim f As Fill

Dim color As color

Dim value As String

For Each s In OrigSelection
   Set f = s.Fill
   Set color = f.UniformColor
   Set value = color.ToString
Next s