If your creating a vignette effect, or just trying to make a gradient selection in photoshop; many times the selection will introduce “banding” because of the light to dark steps given a certain distance. Even with 16 bit files you can have issues with banding depending on the resolution of your file, and the size it maybe printed at. Here is an example. I have an image of a bland sky that I want to create some visual drama and weight towards the top. I first hit Q for quick mask, D for default colors, G for gradient, and carefully click and drag while holding down the shift key. Click and drag on the horizon (the area we want to darken to add visual weight). Note, if the selection appear reversed you can hit Command-i to inverse the selection. Now, next step is go to filter, noise, add noise. Select an amount between .5 - 1. If you hit tilde you will see a black and white representation of alpha channel quick mask is making. Hit Q and your selection will be active. From here you could copy the selection to a new layer and edit the sky. Another way would be to use this selection as an adjustment layer. Select Layer, New Adjustment Layers, Curves, and carefully add some visual weight to your image. If the sky is becoming a bit too colorful or garish, switch the adjustment layer blending mode to Luminosity. If you change your mind on the adjustment range, select the layer mask and transform the mask (Command-T) to the size you prefer.
Keywords: Photoshop, Retouching, Banding, Digital, Asset, Retouch, Noise, Gradient, Fix