Tadasky has used the circle as his compositional framework throughout his career for exploring color relationships with concentric rings of pigment. Through most of the 1960s the compositions were comprised of hard edge bands of color. In the late 60s, he began to push the edges of the borders by applying thick pigment and letting it diffuse on one side of an outer ring of color, as seen in G4 above. Later, the edges were pushed further with ethereal airbrushed rings of pigment and then by incorporating small drops of color around the composition's outer periphery. This presentation examines the range of painting techniques Tadasky used to study the impact of the precise edge, thickness and complexity of borders in his E, G, J, M and N series from the late 1960s through 2011.