In this article we'll show you how to fix noisy photos.
In order to improve the quality of photos in very low light conditions (when not using the flash), cameras amplify the signal from the sensor before it’s digitised and written to memory. Normally this takes place automatically, up to a certain point, but with some cameras you can choose the so-called 'ISO' sensitivity which is a measure of this amplification.
If you (or the camera) use too high an ISO value, though, you can end up with 'digital noise' which appears as an overall graininess, usually with pink and green colours. Similarly, with long exposures odd bright dots, called hot pixels, may result. If this happens in particularly dark areas of the scene, it can look quite distracting.
To remove digital noise use the ‘Noise Reduction (Clear Skin)’ option from Photoscape's Filter menu on the Home tab. However, this technique could also have the negative effect of making your photo take on a soft appearance, so use it sparingly.
It probably won’t have any effect on hot pixels, though, even on the High setting, so you’ll have to adopt a different solution and this will be a largely manual process. There are several methods you could use, including the red-eye removal tool for red pixels, so long as you don’t try it on a red object. However, you’ll probably have to resort to the clone stamp for other colours.
Here are the before and after images:
This article is part of our Fix your photos feature, and uses the free Photoscape image editor from www.photoscape.org. The principles apply to other image editing software, but the steps above explain how to achieve the fix in Photoscape.