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I am preparing to render an animation, and I am experiencing banding colors on a background generated in Blender Internal using a world texture created with a color ramp:

enter image description here

The render generates banding as shown here, highlighted by brown dashed lines:

enter image description here

Earlier versions of the scene used a purer color selection... more in the deep-sea cobalt ranges, and I either did not see banding or there was none...?

Other settings that may be of interest:

enter image description here

Gaussian anti-aliasing on with 16 samples... and I have tried 11 and 8. It is present when no antialiasing is used, as well.

All input welcome!

rcgauer
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  • And, for what it is worth, turning mist off decreases the problem, but does not eliminate it... – rcgauer Oct 15 '16 at 23:13

1 Answers1

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I am very appreciative of information found on blendhelp.com... (Has the site died?) https://www.youtube.com/watch?v=YwrTaXXSZsY

In any case, the solution to my banding involved:

** Select PNG output and 16-bit color depth

** In post-processing, select an appropriate dither amount. I worked between 1 and 2 and seem to get a nice smooth transition.

This explains why I did not see it earlier, as the original color range was probably narrow enough not to generate this banding.

Hope this helps someone in the future!

Please note all input from troy_s below, as these are really helping me dial this in. PNGs did not work as well as Targas, which do not seem to work as well as EXRs.

rcgauer
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    Better would have been a Half EXR container. PNG is a worthless format that both destroys your scene's data (useful if you are going to grade) and also uses an absolutely junk alpha format. Also, bear in mind that posterization is a byproduct of what is known as perceptual quantization. Changing your transfer curve can reduce or eliminate posterization. The sRGB EOTF is quite awful at quantizing data from scene referred data. – troy_s Oct 16 '16 at 19:56
  • troy_s I ended up using TGA... I also tried exr, but I am getting good results with targa with a little less file size... and I am going to mess with curves as soon as I get some frames rendered as a starting point... Thanks or the helpful information. – rcgauer Oct 16 '16 at 21:53
  • The problem is that TGA is also display referred, and I suspect that Blender will mangle up the alpha. I'd strongly encourage you to go with Half EXR at the very least. It's quite easy to demonstrate the reasons why if you are at all interested. You can also try the compressed EXRs if disk size is an issue. – troy_s Oct 16 '16 at 22:13
  • will do so! Anxious to see... – rcgauer Oct 16 '16 at 23:19
  • To start, you might want to learn about scene referred versus display referred models. Try this post to start http://blender.stackexchange.com/questions/46825/render-with-a-wider-dynamic-range-in-cycles-to-produce-photorealistic-looking-im – troy_s Oct 17 '16 at 03:17
  • Wow... a fantastic resource. I am working thru some exr renders and want to consider how my post-render workflow changes from what we have been doing with frames thus far.... but your link sort of points to an "undiscovered country" for me.... Part of the challenge is just the uncomfortable "differentness" of working with exr on monitors and in processes that had been handling pngs and jpgs.... (and of course your link explains why!). I will also wander thru the GitHub links... Your input is scholarly in the best sense, and very welcome...! – rcgauer Oct 17 '16 at 12:14
  • Not entirely scholarly. Discovering how scene referred versus display referred ranges impact your work is a huge mental leap however, and it bears equivalent impact on the work itself. Hopefully you find the impact on the work intriguing if you are using Cycles. – troy_s Oct 17 '16 at 12:23
  • Yes... although even in BI there are instances in which I can see immediate application -- or need for caution. So often in the past, our renders were (giant, enormous, very big high res) single frames for mural work.... so a lot of sins could be covered in post, often just in Photoshop. When we move the assets into motion output, hand modifying 10000 frames seems like less fun and made clear that we need to dial in our workflow. – rcgauer Oct 17 '16 at 12:32
  • But we do primarily use Cycles -- this BI need was a throwback, but I forgot how nice some of its features were.... – rcgauer Oct 17 '16 at 12:32
  • Feel free to drop an email or via http://chat.stackexchange.com/rooms/34814/the-rabbit-hole if you have any questions. It opens up a tremendously different view (literally) on how your work functions, and a massive degree of creativity. The dynamic range in the image makes many things like volumetrics, lens flares, etc. all much more interesting creatively, as well as making HDRI work behave correctly with equal visual energy levels. It is nothing short of an imaging quantum leap, as you will likely discover. – troy_s Oct 17 '16 at 12:39