Jivatma and Paramatma

What is the difference between jivatma and paramatma? What is the size, colour and shape of both?

The Jivatma is atomic. (One ten thousandth the tip of the hair) (Anu).
Paramatma is Infinite (Vibhu).
Example: A drop of sea water(Jiva). The Ocean(Paramatma). They are one in quality but different in quantity.