Why is there a difference in skin tone between the model's face and body

Question: Why is there a difference in skin tone between the model's face and body?

Answer:

1. The skin tone of the body and face must be similar.

2. In a 3D environment, it's best for the lighting distribution on the body and head to be similar (Avoid strong top lighting).

3. Advanced technique: Learn the basics of PSD blending and lighting adjustment. Simply blending images without adjusting the lighting still looks artificial (You can use LightRoom app/plugins, or apps like "Waking Up" which have local lighting adjustment capabilities).