Sphere on the right has a light green opacity filter color.
Filter opacity is the default system, because it provides a more realistic transparency effect. When the Filter option is set in the , the color used by the Filter Color swatch tints the transparency of the material.
The transmission color is that property of a substance that filters certain colors, and allows others to pass. For example, a sheet of red cellophane is a filter that blocks all light not in the red wavelength of the spectrum. By using filter opacity, you can specify a transmission color and achieve strong, saturated colors, no matter how transparent the material.