When I learned first time about frequency separation technique, especially for retouching the skin, it seemed to me like science itself.
You can find a lot of different tutorials, articles and discussions about frequency separation. One of the simplest explanation I found was this video,
which explains it pretty simple, so everyone should get the idea about frequency separation. As many other techniques, this is just another way, how things could be done, and it doesn’t mean, that it should be used all the time. I have used this technique few times, when retouching fabric products ( like cosmetic pouch) which had creases on the photo ( yes, I did try to remove while shooting, but it was impossible). Although I wanted to remove the “blemishes” I wanted to keep the texture of the fabric, and this method came to me as most natural – in certain way, fabric is also “porous” as skin.
Hope you will enjoy&learn!
Vimeo: Skin Retouching tutorial with frequency separation http://ow.ly/udnG6