What is banding?
Banding is an unwanted visual artifact caused by changes in brightness / colour values. As shown above, it is where the image has unwanted lines / bands across what should be a smooth gradient. It’s a common problem with digitised images, caused by there not being enough information to allow a smooth gradient to be shown. It’s often seen in images that show a vignette, or in images that have the sky or a sunset in them.
I use Adjustment Layers a lot. They are non-destructive way to edit an image, to change the curves, levels, colours, hues and saturations etc. But like all methods to adjust colour values, they can cause banding. Although the great thing about Adjustment Layers is they come with a mask, which in this case is very useful, as you can add digital noise to help remove any banding.
To remove banding from a mask, you can follow these really basic steps shown below.
Step 1: Click on the mask. If you want to view the mask directly, without seeing the image itself, you can click on the mask while holding down on the Alt Key. This is what I have done for the below example. It is a great way to see how much digital noise you need to use.
Step 2: Go to Filter –> Noise –> Add Noise
Step 3: The Add Noise box will come up. Depending on the resolution of your image, you will have to adjust this to fit your needs. I personally use 3-5%, but you should experiment with your images. I set the distribution to Gaussian. Being subtle is the key, as if you add too much noise, it will start to show through on the image.
Extra: If you want to add digital noise direct to a layer, then make sure you tick the Monochromatic box. If you do not do this, you will get coloured artifacts showing in the image. A word of warning though, this is a destructive technique, so make sure you do this to a duplicated layer.
And that’s it. It’s that simple. I use this on virtually every mask that I create, and it helps hide banding. Below I have included a real example where banding was an issue. The image had a Solid Colour Adjustment Layer that had a strong gradient added to it. This caused banding, so I used digital noise to hide the banding.
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