VARNA/COMPLEXION

 As per ayurveda, varna is the color of the skin or any other entity.
The color of skin could be Sahaj(by birth) or Jatottar(acquired).
Avabhasini is the layer of the skin that displays the Varna(complexion) and Prabha(Lustre)  of the body.
Types- There are four types of varna : Gaur, Krishna, Krishnashyam & Gaurshyam.
These develop during foetal life. We may say that the wide spectrum of skin colors result due to admixture or association of various mahabhutas(basic elements) with Agni(fire) mahabhuta.
Gaur                 - Tej + Jal
Krishna             - Tej + Prithvi
Krishnashyam   - Tej + Prithvi + Akash
Gaurshyam       - Tej + Jal + Akash
According to Vagbhatta, the color and texture of semen of father conjures the color of the offspring.
Conceptual prediction of the skin color of the offspring is as follows-
white like ghee-gaur
like oil- krishna
like honey-shyam
Mothers diet during gestational period also affects the varna of child. If a pregnant woman eats more Kashaya rasa( pungent), she is likely to bear a shyam varna baby. Excessive intake of madhur rasa(sweet) and diet which is rich in ghee results in gaur varna of offspring.It is indicated that even the color of food and other articles used by the woman affects the skin color of the foetus. In addition to the above, other factors like the type of shukra, kul, jati, vansha(genetic background), desh(area) etc are also mentioned which may cause some impact on the determination of the skin color.