Week 4 – Noise Reduction

Filter > Noise > Reduce Noise

Noise appears as random extraneous pixels that aren’t part of the image detail. This is usually caused by shooting in low light, under exposure or usage of a high ISO. Noise appears in two forms, first luminance noise which appears grainy or patchy and colour noise which appears as coloured artifacts. Luminance noise may be more predominant in one channel, usually the blue channel. The noise of each channel is adjustable separately in advanced mode, first make sure to examine each channel to see if noise is dominant in one. This will help preserve more detail in the image.

This is the original version of the image I intend to work on

These are the settings I decided upon after some experimentation, I feel that I reduced the noise enough without the image appearing over soft.

Strength – Adjusts the amount of luminance noise reduction applied to all of the channels.

Preserve Details – Preserves edges and fine image details and surfaces. A value of 100 preserves the most image detail, but reduces luminance noise the least. Balance the Strength and Preserve Details controls to fine‑tune noise reduction.

Reduce Color Noise – Removes random color pixels. A higher value reduces more color noise.

Sharpen Details – Sharpens the image. Removing noise reduces image sharpness. Use the sharpening control in the dialog box or use one of the other Photoshop sharpening filters later to restore sharpness.

Remove JPEG Artifacts – Removes blocky image artifacts and halos caused by saving a image using a low JPEG quality setting.

Final image with noise reduction applied.

Noise Reduction in Camera RAW

 With a RAW file another technique to reducing noise would be to use the capabilities built in to Camera RAW. I will complete this process using the same image.

By selecting the detail tab found in Camera RAW will open sharpening and noise reduction tools. Luminance reducing luminance noise and colour reducing colour noise. Zooming in to around 100% provides you with a better idea of the amount of noise reduction applied.

Original Image

Luminance and Colour noise reduction applied


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