Part IV is up! Here's the 4th part in the series I'm doing on editing portraits from start to finished product. Frequency Separation is an extremely effective and powerful tool when retouching skin and portraiture. It can be very effective, but has to be done subtly as it can be overpowering and make skin look overdone or fake. So, without further ado, here is how I approach Frequency Separation and why I do so!