Keep the noise down
1 Improve the exposure
Open noise_start.dng in the Library module. Toggle open the Metadata tab. To take this shot we used a noise-inducing ISO12800. Zoom in to see the noise more clearly. In the Develop module, drag Exposure to +1.75, set Blacks to -64 and Vibrance to +29.
2 Reduce colour noise
In the Detail panel’s Noise Reduction section, drag Color to 0 to see the chroma noise speckles. Slide it to 25 to remove them. The Detail tab provides a balance between reducing colour bleed and colour speckling. Drag it right to reduce bleed or left to reduce speckling.
3 Reduce luminance noise
The Smoothness slider is designed to remove low frequency colour mottling, but in this case the default setting of 50 gives good results. To soften the remaining luminance noise, drag the Luminance slider to 32. This reduces luminance noise, but it also blurs image detail.
4 Preserve the detail
The Detail tab enables you to get a balance between smoothing out luminance noise while protecting detail. Drag it right to sharpen blurred details, or left to blur noise. The default of 50 produces an effective compromise. You could also try increasing Contrast.