Howard5252 wrote:
The first one uses colors picked from a color wheel; violet and yellow are complementary colors on the wheel.
The second one uses a glass ball approx 2" in dia. / it is sitting on a CD disc and is lit from below / the camera is pointing straight down. The lighting through the edge of the CD creates the white circle and as the light is scattered by the glass it skims the disk, giving off the colors. The black around both images was cleaned up in PS Elements