On Sep 14, 2005, at 9:51 PM, Shel Belinkoff wrote:
For what are the Luminance Smoothing and Color Noise Reduction
sliders on
the Detail tab used?
They are both noise reduction tools, operating on the pre-RGB channel
transformed data in Lab color space.*
- Luminance smoothing works on the L* channel. It essentially
applies a median filter to smooth luminance noise.
- Color Noise reduction works on the a* and b* channels,
again applying a median filter to reduce chrominance noise.
This works to reduce the red-green mottling that underexposure
produces.
In general, if you are working with a properly exposed image, there's
no reason to change the default settings. If you have an
underexposed or otherwise noisy image, making adjustments during RAW
conversion might prove more effective than using noise reduction
techniques after rendering to RGB.
It's useful to experiment with a noisy image to learn what they do.
If you want to muck with them, I recommend setting the preview window
to 200% magnification so you can see precisely what effect they're
having on the pixels.
Godfrey
*Lab color space ... the most complete color representation
available. See http://en.wikipedia.org/wiki/Lab_color if you would
like to know more about it.
