Violet genes are incompletely dominant.
Violet Cobalt (female)
Violet Cobalt (female)
SF- Single Factor
DF- Double Factor
The Violet gene is dominant over Non-Violet. Violet, in the Single Factor form, makes the bird a half shade darker. For instince, a Sky Blue bird with one Violet gene will appear to be a color between Sky blue and Cobalt. For this reason, sometimes it is difficult to distinguish between Cobalt and Violet Sky blue.
Double factor Violets are a different story. Being Incompletely Dominant, Violet genes will combine with each other. When a budgie has 2 Violet genes (Double Factor) the genes combine and to form a darker body color shade. A DF Violet Sky Blue can appear as rich in violet color as a SF Violet Cobalt (a true "violet"). SF and DF Violet Cobalts are a bit harder to distinguish between.
Opaline Violet Cobalt (male)
Violet Dark Green Male.... Violet Sky blue female
Sometimes a bird with a Violet Factor will appear to be a different shade.
For example, in the pictures above, the Violet Dark Green Male resembles an Olive while the Violet Sky Blue female could be mistaken for a Cobalt.