Smooth out undesirable image noise while preserving detail
Lauren Scott shows you how to smooth out undesirable image noise while preserving detail using the Reduce Noise filter
When shooting with a traditional film camera, you could use film with different ISO speeds to capture more detail in low-light conditions. The faster (higher) the film’s ISO speed, the more sensitive it was to available light. A fast film enabled you to avoid using slow shutter speeds in low light, so you could capture detail without the need for a tripod. You could also shoot handheld in locations where flash was prohibited, such as in a museum or church. Today’s digital cameras can reach blistering ISOS compared to the film cameras of yore, but bumping up the sensitivity of the sensor isn’t without any noise at all. You’ll know that the higher you push your ISO, the grainier your images become, but did you know that there are two types of digital noise – luminance (greyscale) and chroma (colour)? Luminance noise appears throughout the tonal range of the image as tiny dots. It can be compared to grain in analogue film, so it isn’t as undesirable as chroma noise, which manifests itself as multicoloured speckles. However, you may still want to smooth out high Iso-induced luminance noise to get a more pristine digital photo. When reducing the presence of luminance noise, you have to be careful not to blur important details, or end up with an image that looks soft and muddy. Follow these quick steps for an idea on how to get started.