Let's De-Noise a Noisy Photo

What exactly is ‘noise’? Noise or digital noise as we often call it, is a type of distortion that looks similar to what ‘grain’ was/is with films. There are several types of noise, but to keep things simple, we shall mention only ‘luminance’ (brightness) noise and ‘chroma’(colour) noise.

- Rohinton Mehta

Our photos can be noisy due to several reasons. Some reasons are:

1. Using high ISO sensitivity

2. Underexposing the photos and then trying to get detail in dark areas by ‘opening up’ the brightness in an image editing program

3. Using a warm/hot imaging sensor (such as while using the camera in an overly warm environment)

4. Using very long exposures (this heats up the imaging sensor)

5. Trying to enlarge a very small portion of the image

There are several ways to mitigate (reduce) noise in post-processing. For this write-up, we shall use top-notch software from Topaz Labs, called DeNoise AI. AI stands for Artificial Intelligence. Why are we going to use Topaz DeNoise AI and not any other de-noising software? Simple. I own a copy of Topaz DeNoise, which I find immensely good. Also, though there are several other good noise-reduction software available, I haven’t used them all.

In the past, I had never used ISO sensitivity higher than ISO 5000. The first time I used ISO 5000 was during a trip to Corbett National Park in 2017. At that time I was using an APS-C camera body (Nikon D500). Light levels were quite low and I was hesitant about using high ISOs, but had no choice.

At that time I used a lower version of Topaz DeNoise and was really surprised at the results. Yes, noise was evident even after using the software, but it was acceptable.