Quote:
Painters discovered that the inclusion of an s-shaped curve in their composition added a sense of movement to an otherwise static image. The s-shape is aesthetically pleasing and is capable of standing on its own in an image. Show us an image where the "S" curve serves as the primary focus of your image.
( dpreview )
Quote:
Curves can be used to add a touch of grace and beauty to a photo. Curves are the element of elegance in photographic imagery.
First, curves function similarly to diagonal lines in that they tend to make an image more dynamic.
Curves are abundant in nature and allow the photographer to add impact and grace to her image. Some examples are the curve of the ocean’s waterline during a sunset, the curve of a bird’s feathers, and tall bent grass in a late afternoon’s light.
( Ron Bigelow )
Few more refs:
P52-1-21 Winning entry by venturi
P52-3-40 Winning entry by Tamia
P52-4-21 Winning entry by Bruce

(Photos for the Week #17 competition are to be taken between Apr 8, 2013 and Apr 14, 2013.)
via PF.com