Adobe Photoshop Lightroom CC - Manual (Page 176)

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Processing and developing photos
Last updated 4/20/2015
Reduce image noise
Image noise is extraneous visible artifacts that degrade image quality. Image noise includes luminance (grayscale) noise,
which makes an image look grainy, and chroma (color) noise, which is usually visible as colored artifacts in the image.
Photos taken with high ISO speeds or less-sophisticated digital cameras can have noticeable noise.
1 (Optional) Zoom in on the photo to at least 1:1 to better see image noise and the effects of the sliders.
2 Drag the 1:1 image preview in the Detail panel of the Develop module to see the area of the photo that looks grainy
or displays colored artifacts.
3 In the Noise Reduction area of the Detail panel, adjust any of the sliders. The first three sliders affect luminance
noise. The last two sliders affect color noise.
Luminance Reduces luminance noise.
Detail Controls the luminance noise threshold. Useful for very noisy photos. Higher values preserve more detail but
may produce noisier results. Lower values produce cleaner results but may also remove some detail.
Contrast Controls luminance contrast. Useful for very noisy photos. Higher values preserve contrast but may
produce noisy blotches or mottling. Lower values produce smoother results but may also have less contrast.
Color Reduces color noise.
Detail Controls the color noise threshold. Higher values protect thin, detailed color edges but may result in color
speckling. Lower values remove color speckles but may result in color bleeding.
To turn off noise reduction, set the Sharpening Amount slider to zero or click the Detail panel On/Off icon .
Correct lens distortion and adjust perspective
About lens distortion
Camera lenses can exhibit different types of defects at certain focal lengths, f-stops, and focus distances. You can correct
for these apparent lens distortions using the Lens Corrections panel of the Develop module.
Vignetting causes the edges of an image, especially the corners, to be darker than the center. It is particularly noticeable
when the photo contains a subject that is supposed to be an even shade or tone, such as the sky in a landscape image.