In this episode, I cover the amazing Noise Reduction tool from Adobe Lightroom 5. Before attempting to reduce Noise one should know what Noise really is where it comes from.
What is Noise in Photography?Noise is to Digital Photography what Grain is to Film photography. They are both artefacts which appear when shooting in low light. The reason is that in low light, by definition one does not have much light information and there needs a way to increase what is being recorded. With film, it is about choosing a high ISO/ISA film which is more sensitive to light than a standard 100 ISO. With digital, it is just about turning a knob to the high ISO value which will amplify the signal received by the camera sensor. In a way, noise to photography is what distortion is to an electric guitar. If one only turns up the volume, then one can hear the guitar sound but if one cranks up the volume, while the sound is louder one can hear some weird “noise”, parasites, that are not coming from the guitar per se but the microphones and amplifier.
Two types of Noise in Photography
- Luminance Noise is very similar to the film Grain and appears as dark/grey pixels:
- The second type of Noise in photography is called Colour Noise which appears are Red, Green or Blue pixels in some areas where they should not be:
How to reduce/remove Noise using Adobe Lightroom 5?One obviously starts in the Develop Module and the feature can be found in the Details panel on the right:
Step 1 – Only use the Noise Reduction tool at the EndIt is very important to treat the Noise at the very last step in your Editing workflow. This is because if you were to apply any more changes such as changing the contrast, the exposure, the clarity or else, you could alter the result of the Noise Reduction you previously got and would end up having to re-tweak the tool again.
Step 2 – Zoom inLike when using the Sharpening tool in Lightroom, one needs to zoom in at least at 1:1 ratio to properly appreciate the effect of the changes being done by the sliders. While there is a little window inside the panel, I do not use it as I’d rather utilise the entire central preview screen and zoom at 100% (1:1).
Step 3 – Start with treating the Colour NoiseBy default (as you can see in the screenshot above) Lightroom applies the Colour Noise Reduction by default at 25. This is because LR knows that by default you are bound to have some Colour Noise which can easily be treated. Do not forget that Noise is predictable given the ISO and the camera and LR knows which camera you have used. The way the tool works to correct the Colour Noise is to desaturate any vivid pixel that appears unevenly in some areas of your image. This is the reason why one needs to treat the Colour Noise first.
Under Colour you will find 2 other sliders
- Detail: Which basically reveals/fine tune whatever treatment you applied to your image by moving the Colour slider.
- Smoothness: This is a new feature in Lightroom 5 which came out in late 2014. It is meant to smoothen the treated Colour Noisy area of your image which can appear like smears:
Step 4 – End with the Luminance NoiseLuminance Noise slider is the main feature of the Noise Reduction tool. by moving the slider to the right you end up smoothing your image and reduce the appearance of the “grain”/grey/black pixels in the areas of your image where they should not be. One has to be careful when using the slider as the higher the value the smoother the image becomes and you end up trading Noise for details: There isn’t really a value fits all. It depends of your photograph, the subject, the camera used and the light condition of course. Similar to the Sharpening tool, one can hold the Alt/Option key (on the mac) while moving the Luminance/Detail or Contrast slider and the preview appears in monochrome. Personally i do not use it as i like to assess the amount needed by looking at the final edited version.
Under Luminance, you will find 2 other sliders
- Detail: Which basically reveals/fine tune whatever treatment you applied to your image by moving the Luminance slider.
- Contrasts: This will add more contrast to your image which will have been smoothened by the Luminance slider. As any contrast it darkens the dark pixels and brighten the highlight pixels.