ABSTRACT
Removing noise using multiple exposures Here is a technique for reducing noise that makes use of the Stacks feature in Photoshop, where you can blend a series of identically shot photographs to produce a single image in which all the noise artifacts are smoothed out. This technique works very well for those situations where you are shooting pictures of still-life subjects in low light conditions but don’t have access to a tripod. However, you can only use the following technique if you have the extended version of Photoshop CS3 or later. Here’s how it works. Once you have aligned the photos using the auto-align method described here, the Median Stacks rendering method averages out the pixels at each point in the image. What you end up with is an image that not only will be noise-free, but may well appear smoother and sharper than the individual captures. This is because the rendering process also smooths out those shots where there was a slight amount of blur. There was also another Stacks processing technique described on pages 138-141, but this too can only work if you are using the extended version of Photoshop.
