Photoshop: Why do I see banding in dark gradients?

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  • Updated 6 years ago
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When I crate dark gradients. They are not smooth. Look at the screenshot. The screenshot should be a radial gradient. But you can see circle shaped color areas instead of a smooth transition. Is this a problem of Photohop or monitor limitations?
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Kenny

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Posted 6 years ago

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Chris Cox

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You're looking at the limits of 8 bit quantization. 16 bit would be numerically smoother, but your display is probably also limited to 8 bits/channel.

You can make it visually smoother by enabling dithering when you create the gradient, or adding a small amount of noise (0.5% or less).

The display quantization can be made worse by your display profile - so make sure that your display profile doesn't have any odd kinks in the tone transfer curve.
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Kenny

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The dithering was already on. Adding a noise layer on top of the gradient makes it look smoother. I noticed with 16 bit in photoshop it is much smoother. Also when I export the image it gets smoothed automatically. So the problem seems only visible in the photoshop view.

Here is the exported image (without, with noise):


And here is a screenshot of the Photoshop view:
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Kenny

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I used the dithering option on the gradient - it does not help. Actually I am using a vector shape with gradient overlay. Tough it makes no difference to the normal gradient tool. What should I check on the display profile? I can only recalibrate it. Also I am wondering why using 16 bit works without that banding. That makes me think it is not a problem of the display but with photoshop. And if you see the banding too, then wouldn't you also have a display problem?
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Chris Cox

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I don't see banding in the document, just in your screen shot - that means that it may be a problem with your display profile, or your GPU/driver.
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Kenny

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Do you see banding in the very first image? Which I started the thread with. I will add more more images with gradient and banding below.
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Chris Cox

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In the exported image, I don't see any obvious banding, only in your screenshot do I see banding.
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Kenny

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I mean the one I started this whole "question" with.
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Kenny

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I am working on a Photoshop file where exporting does not smooth the gradient enough tough. I have to convert the image to 16 bit. So I would have to do my designs in 16 bit or create the gradient in a separate photoshop file for exporting only.
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Kenny

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Or would have to convert to 16 bit before exporting.
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Kenny

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It is a white gradient with 10% opacity over flat dark background - if you want to try it yourself. They are not screenshots but exported with Photoshop.

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Chris Cox

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The second image shows some banding, the first does not.
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Kenny

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I have to look down on the screen from a higher position. That lightens the image up (because it is a lcd screen). Then I can see the banding better.
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Chris Cox

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doing that is just exaggerating the quantization already present on your display, and likely to show banding regardless of the data.
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David Jensen

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Two issues here.
Transparency in gradients is not dithered.
Setting a Layer with a gradient on it to 10% opacity posterizes the layer causing the original dithering to be ineffective.
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Kenny

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That's correct. I tried making the gradient without transparency from one color to the other. It brings in some dithering. The result is a bit smoother. Tough I still can see some bandings if I look closely.