digitaljockey

Smart Object Stack Mode is a good way to reduce noise and remove unwanted objects from a scene. For example, if you have a photo of an art gallery full of people but want it to be displayed as an empty gallery, or of a street with passing cars but want it to be an empty street.

Or if you have a very low light situation with a lot of grain, you can take several pictures and Photoshop will combine those to reduce the grain.

into the wave