B&W noise removal technique in Lightroom

A while back I wrote about making black & white photos using Lightroom adjustments and I still use these techniques today to convert my color photos to grayscale images. At the very end of that entry I mentioned a technique for desaturating images using the Hue-Saturation-Luminance panel in the Develop module that I first learned from reading Matt Kloskowski's Lightroom Killer Tips. Instead of just clicking on the grayscale adjustment button, you go in to the HSL panel and pull the saturation back to -100 on all the color sliders. This lets you do some cool things.

Panel 3 is where the magic happens.

Frankly, I am against noise. Not that I want everything silky smooth, but when it gets in the way of content, I want it gone. So I've used Noise Ninja's plug-in for Lightroom but frankly it's a pain having to generate a new file and then re-import it in to my catalog and I'm eager for them to come up with a system where I don't have to leave the Lightroom environment. Now that I know about this next trick, I don't have to rely on outside help very much.

HSL saturation sliders pulled back, but Presence sliders still at zero. Notice the noise.

In the past couple months I discovered something about this technique that has made it much more useful to me.. Once you've pulled your Saturation sliders in the HSL panel back to -100, it turns out you can still use the Saturation and Vibrance sliders in the Presence pane to adjust your photo. One of the big benefits of this is that when you reduce the saturation, it tends to eliminate a great deal of noise. Not just color noise, but luminance noise as well. And it seems to manipulate the image in such a way that you don't get the same amount of blurring that you do when you use the Noise Reduction sliders in the Detail panel.

I play around with both sliders depending on the image, just to see what it will do. If I don't crank the Saturation slider all the way down, I can use the Vibrance slider to modify the effect further, but if Saturation is all the way to the left your Vibrance slider doesn't have any effect.

HSL Saturation sliders pulled back, and Presence Saturation slider also pulled back.
Note the difference in the amount of noise, especially in darker tones.

Now, fair warning: you will sometimes get a tonal shift when you pull this slider around. Generally I see that happening more in highlight areas, and sometime I have to go back to my Tone Curve to tweak a photo after I've applied the noise reduction. But it works so well that I find it is one of the first options I go to on many B&W photos, and it has saved a handful of them that might otherwise have been marked with the little black flag with the "x" in it.

One other little timesaver: make a preset of the the -100 settings in the HSL panel, and then you won't have to pull them all back one at a time each time you work on a photo. Click the "plus" sign by the word Presets on the left-hand panel, and then click "uncheck all." Then just click on "Saturation" in the color panel. (The "Treatment(Color)" and "Color" boxes will automatically check on when you click this. That's fine.) Name it something like "Desaturate for B&W" and you can use it any time, in any catalog you've got after that.

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