Remove banding for website display

[rpagliari]

I add medium/heavy vignetting to some of my images, by choice.

As my images are B&W (16 bit), I then typically add uniform monochrome noise when I see banding. Occasionally, though, I see banding on the image rendered by the website I uploaded to, but not on my screen (lightroom, photoshop and preview look perfect).

So far, the only way around I've found to mitigate the problem is to use more noise and change the noise type to gaussian mode.

Are there other/better methods?

[Jim Noel]

Film!

[Ken Lee]

What file type are you using ? Are you seeing the banding only in your browser ? Which browser ?

JPG is limited to 8-bit and depending on compression we will often see banding.

Have you tried PNG files instead ?

[rpagliari]

What file type are you using ? Are you seeing the banding only in your browser ? Which browser ?

JPG is limited to 8-bit and depending on compression we will often see banding.

Have you tried PNG files instead ?

I'm using jpeg and opened the image in Chrome. I usually don't have problems, even when gradients are subtle but I have an issue with this particular image.

I will try with png, haven't thought of that. The websites I share images with, only accept jpeg.

With jpeg I can remove the banding by applying gaussian noise, instead of uniform noise.

[Ken Lee]

The whole point of lossy compression used by file types like JPG is to remove information. That almost always results in banding if your image contains any subtle gradients. Sharpening can do the same.

The sites you are using may be applying additional compression and sharpening without your knowledge, in order to save on their own storage expenses and "improve" your images.

If your images start out as 16-bit you should convert them to JPG as your last step, not your first. Be sure to work in the sRGB color space and tag your JPG files with that profile.

You might find this brief article helpful: How (and why) to Convert Images from 8 to 16 bit in Photoshop (http://www.kennethleegallery.com/html/tech/index.php#histograms). The last paragraph contains the important information. I don't know if there is a corresponding method in Lightroom.

If those web sites only allow JPG but PNG files work for you, perhaps you should consider different sites.

[rdeloe]

When you export from Lightroom you choose not only the file format, but also the dimensions, bit depth and colour space. A good place to start is ensuring that you have those all set correctly. For example, this forum wants images no larger than 800 pix in the long edge. If you use a larger number, it gets downsized (meaning you've lost control of how the file is displayed).

If this link is still up-to-date (https://cameratico.com/guides/web-browser-color-management-guide/) then Chrome is not colour managed. In other words, you might be tagging your files properly on export, but Chrome ignores that. Have you viewed your exported files in Mozilla Firefox (which is colour managed)?

[jp]

Try some different quality percentages on export and see how that affects banding. You adding noise is probably just a ruse to create less compression with the jpeg format. I generally use 80-95% quality.