Image Stacking to Reduce Noise
Photoshop CS6 Tutorial
How to Remove Image Noise with Image Stacking in Photoshop
Depending on your digital camera and lighting conditions, you may notice you excessive noise in the final image. With this technique you can reduce the amount of noise by placing your camera on a tripod and capturing multiple images of the same scene. The images are averaged in Photoshop and the noise is greatly reduced.
For best results, use a tripod and timer mode when capturing your images to prevent camera shake as much as possible. This method is recommended for stationary objects and scenes.
With your camera set to timer mode and on a tripod, take a series of four images of a scene. Nothing should be moving in the scene.
Open Photoshop and choose File > Scripts > Load Files into Stack.
In the dialog box, click the Browse button to find your four images. To select multiple images in the same folder, click the first one, then Cmd-click (PC - Ctrl-click) to select the remaining images.
Click Attempt to Automatically Align Source Images and Create Smart Object after Loading Layers, then click OK.
The images are added as a single smart object layer. Select the smart object layer, then press Cmd/j (PC - Ctrl/j) to duplicate the smart object layer.
With the upper smart object layer selected, choose Layer > Smart Objects > Stack Mode > Median.
Zoom in on your image and turn the visibility on and off for the top layer. Notice the noise reduction achieved by the image stacking.