LAB colour and noise

[John Chardine]

Not a query but a comment.

I am reading Dan Margulis' excellent book Photoshop LAB Color (not the way I spell colour but that's another topic!).

I thought I would put to practise his thoughts on noise and sharpening in LAB. Here's an image made with the Canon 1D mark IV at ISo 6400. The mark IV does pretty well with noise anyway but I wanted to see what I could do in post processing to reduce. I converted to LAB and ran Noise-Dust and Scratches at 6 pixels on the A and B channels. Then ran Noise Ninja NR on channel L, masking out the bird. I am pleased with the result.

Date: 16 April, 2010, Time: 12:44h
Model: Canon EOS-1D Mark IV
Lens: EF400mm f/5.6L USM +1.4x @ 560 mm
Program: Aperture Priority
ISO 6400, 1/800s, f/10
Exp. comp.: +0.3
Flash: on, Flash exp. comp.: -1.4

[Desmond Chan]

I converted to LAB and ran Noise-Dust and Scratches at 6 pixels on the A and B channels. Then ran Noise Ninja NR on channel L, masking out the bird. I am pleased with the result.

John, why ran Noise Ninja on on L and not either a or b, if I may ask? If I remember correctly, isn't b has the most noise?

Would you mind posting the "before" picture for comparison?


As a side note, Dan has some more videos on LAB on Kelby Training, if anyone is interested.

[Charles Glatzer]

Hey John,

You can change the sharpening/noise reduction layer blend mode to luminosity, or after applying effect go to Edit > Fade ... and change the blend mode to Luminosity to avoid effecting colors. At times you can benefit by applying NR to a specific Channel in RBG mode as well.

Chas