If you’re capturing RAW image files—which you most definitely should be—you have the ideal opportunity to reduce the noise in Adobe Camera Raw or Lightroom. Both of these approaches use the same technique to reduce noise.
In ACR, choose the third icon on the panel of Image Adjustment tabs found on the right side of the dialogue box. That is the Detail adjustment, and it offers a direct connection to the noise reduction controls. The sharpening sliders are at the top, but below that are the controls for noise reduction. The top noise reduction section, Luminance, defaults to zero but can be increased as needed to minimize “luminance noise,” or pixels that are amplified to brighter specks where they shouldn’t be. This happens when the signal is boosted by high ISO or long exposure. Some pixels get “hotter” than others and luminance noise is exaggerated, giving a textured appearance similar to the grain that came with high-ISO film.
The Luminance slider helps bring down this noise, while the Luminance Detail slider helps maintain image-forming detail. Too much noise reduction can create a plastic, fake appearance. The detail slider helps mitigate that effect; it comes up automatically once you move the Luminance slider and from there can be adjusted manually. The Luminance Contrast slider helps keep the image from becoming muddy and flat, maintaining brightness in the pixels that need it. There’s no specific formula for how much of any of these settings is ideal, but too much is never a good idea as it removes the realism from an image. To ensure you don’t overdo it, make sure to zoom in to 100 percent to ensure you can see the changes made as you adjust these sliders. And turn on the before-and-after view (by typing Q or clicking the view icon in the lower right of the preview window) to see a side-by-side comparison of just how much impact your adjustments are making.
The next section of the Detail panel is for repairing color noise, which often appears as a rainbow pattern of amplified pixels, often especially evident in darker tones and consistent areas without much detail—such as skies, for example. The sliders work in much the same way as with luminance noise, but they’re specifically designed to target color noise instead. A higher setting on the Color slider brings down color noise—with too much again creating that plastic appearance. Color Detail helps to maintain important image-forming information, particularly in small areas of fine detail and edges, while Color Smoothness makes sure speckled or mottled areas of color end up smoother and more uniform. When finished with the noise reduction, click the Open Image button to open the photo in Photoshop for further editing.
If you’re a Lightroom user, good news: The processing engine in Lightroom is the very same one used by Adobe Camera Raw. That means the noise reduction approach—as well as the interface—are virtually identical. The only slight difference is in the names of the sliders, although their effects are the same. In Lightroom, the noise reduction controls are found in the Develop Module, under the Detail tab. Below the Sharpening sliders, look for the Noise Reduction heading, where you’ll find Luminance, Detail and Contrast sliders for correcting luminance noise, and below that the Color, Detail and Smoothness sliders for eliminating color noise. They work in just the same way as explained above for the corresponding sliders in Adobe Camera Raw.
Those who don’t shoot RAW image files have a bit of a tougher time removing noise, but it can still be done in Lightroom as well as Photoshop. Open an image in Photoshop and look for the Reduce Noise option under the Filter menu’s Noise heading. A pop-up window appears, offering first a checkbox that shows a preview of the effects as applied. Ensure this is checked. Then the basic or advanced radio button keeps it simple and straightforward or adds the ability to apply these noise reduction effects to each individual color channel. If you’re serious about rectifying green channel noise, for instance, this can be an ideal approach to localize adjustments precisely where they’re needed—helping to retain important detail and target the correction specifically to noise. Otherwise, Reduce Noise’s sliders may be named somewhat differently, but they’ll have a similar impact to the noise reduction sliders in ACR and Lightroom. The top one is strength, on a scale of 1 to 10. The higher the strength, the more noise (and detail) are blended away. The Preserve Details slider helps to focus the effect on the noise without destroying image-forming information; a higher number here translates to more detail with less noise reduction. So far, these sliders are particular to luminance noise. This third slider, however, is built to target color noise. The Sharpen Details slider helps to maintain contrast in fine edges, making sure not all of the image-forming information is blended away with the noise. Lastly is a new option (when compared to Lightroom or ACR) and it’s specifically built for JPEG files. It’s the Remove JPEG Artifact checkbox. When a JPEG is saved, the compression creates artifacts that essentially become “noise” to the “signal” of the actual image detail. By checking this box, the noise created from saving JPEGs—particularly highly compressed JPEGs—is mitigated.
One of the major benefits of applying noise reduction in Photoshop is the ability to isolate the effect in specific areas of the frame. By selecting the background, for instance, and leaving the subject untouched, a differing amount of noise reduction can be applied to primary and secondary image areas—perfect for eliminating more noise in the background and less noise in the subject where detail must be maintained.
Beyond Adobe, a variety of software companies have also worked on the problem of minimizing noise from digital image files. The NIK collection from DxO includes a great noise-reducing plug-in called DFine, available as part of a suite of plug-ins that sells for $69. Another option is Topaz Labs and its DeNoise ($79) and DeJPEG ($29) Photoshop plug-ins. DeNoise is a more traditional noise reduction tool, while DeJPEG eliminates compression artifacts and repairs damaged areas of JPEG files, turning low-quality files into higher-quality images.
PictureCode’s Noise Ninja software was long a popular Photoshop plug-in specifically for improving noise in image files of all types, but now that functionality has been rolled into the standalone RAW processing application known as Photo Ninja. Beyond simple noise reduction, Photo Ninja provides an entire alternative RAW image processing solution for $129.