Many times during post-production work on a photo you may need to add some kind of rendered gradient into the background or maybe even into an object in the photo. And most of the time these Photoshop generated gradients will have banding issues.
What is banding? Banding is when you can see distinct rings in your gradient with hard edges where the gradient goes from one shade to another. It will make your gradient look amateurish and can even get an image rejected here at DreamsTime. It's happened to me!
Here's a great solution which I've cobbled together from a few different online tutorials I found that fix this nagging problem:
1. Make a copy of the gradient layer.
2. Blur that copied gradient layer quite a bit with a Gaussian Blur filter set to about 30 pixels.
3. Make a new layer above the blurred copied layer and set this new layer to Overlay with a 50% gray fill. THE EASIEST WAY TO DO THIS is to click the new layer icon in the Layers pallet while holding down the Option key (Mac) or Alt key (Windows) to get the New Window dialog box where you can select Overlay as the layer's Mode and check the "Fill with Overlay-neutral color (50% gray)" check box.We'll call this new layer the Gray Overlay layer.
4. Now add noise to the Gray Overlay layer by going to
Filter --> Noise --> Add Noise
and add just enough noise to reduce the banding. NOTE: when you are in the Add Noise dialog box, select Uniform for the Distribution setting and be sure the Monochromatic check box in NOT SELECTED.
If you're happy with the way it looks at this point, you're done! But usually I will select a slightly darker color from the bottom edge of the gradient, set my Brush Tool to 10% opacity and very lightly brush around the bottom corners for that slightly vignetted effect. THIS MUST BE DONE ON A NEW LAYER ABOVE THE GRAY OVERLAY LAYER. And do not overdo this brushing because banding could be reintroduced into these areas if you brush in too much.
I've attached a few images I have up here on DreamsTime where I employed this technique.