Whether you have a lifelong love of photography or you’re a budding photographer, you understand not every picture is perfect. The tone of the picture might seem odd in one, or your subject may have moved too quickly in another. Often you’ll find a better version if you take multiples. One problem that can plague an entire set of pictures is noise.
What is Noise?
Have you ever looked at scanned photos or a picture in a magazine and thought it looked grainy? In film photography, the grain of a photograph is determined by ISO sensitivity to light. If a photo is shot with a high ISO, it will appear granulated. The same principle applies in digital photography but the grain that is visible is called noise. Some noise is worse than others (kind of like your daughter's taste in music). One form of noise may appear as spots of discoloration and can ruin an entire image.
How is Noise Formed?
Shooting in low light is a common cause of noise, but the capture system you use will cause different levels of noise. Some digital cameras are equipped with array sensors. When you take a picture, primary colors combine to create abnormal patches of color. In scanned photos, noise may only be noticeable in the shadow areas of the picture because they are scanned at a high resolution. The same principle applies to linear array cameras.
Fixing a Noise Problem
Different people can accept different levels of noise so there’s no prescribed formula for ideal photo enhancement. An enthusiast may be fine with noise that a professional finds unacceptable. The subject of a picture can also determine how much noise is appropiate. An action shot with shadow noise is more tolerable than a still of a painting. Try to shoot at a low ISO and employ noise reduction software. If you’re trying to color correct scanned photos, be wary of the pixels used to balance color. Noise pixels can cause the entire photograph to become discolored. If you aren’t sure whether noise is present in your scanned photos, magnify your image. The answer is in the details.
Your scanned photos are comprised of important life events, vacations and random moments. Don’t let the noise of your scanned photos drown out your memories!