Vibrancy and Saturation

Thom Hogan posted a recent article on the difference between color saturation and vibrancy, and it's well worth the read for those interested in how to manage colors in post.  Most cameras have a "vivid" setting that allows users to dial up color saturation in camera, but often these settings blow out colors we'd rather leave alone.  Ken Rockwell is fond of VIVID++!!!BANGBANG!ONE!, but notes that this usually destroys skin tones, for example.

Color correction is a big subject about which I know comparatively little, but he mentions a significant issue when increasing color saturation:  linearity.  A heedless linear increase in color saturation across all spectra will lead to poor results.

While Photoshop has (I'm led to believe) a vibrancy control, the Gimp does not.  (There is a vibrancy plugin, but as far as I know it's not standard.)

A suitable method for increasing saturation in a non-linear fashion is to decompose the image into an appropriate color space and modify the saturation curve.  For the following example, I'll use an image from my shots at Hopewell Furnace.

Recent Trip

I recently went on a day-trip with some friends to shoot locally.  We had pondered doing some geocaching during a four- or five-hour trundle around the countryside but ended up spending most of our time at a historical furnace.  The day was mostly overcast, and I ended up shooting with a -1 or -2/3 exposure bias most of the time.  The 55 micro was on the camera most of the time thanks to its sharpness and contrast, but I had a few good shots with the 85 and 400 as well.