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8bit banding due to insufficient spatial processing fidelity. not uncommon with any kind of gradient, glows, blurs and an assortment of other effects. Switch your project to 16bpc or use some post-processing tricks like adding additional grain or using one of those debanding filters as they are included e.g. in Tinderbox.
Yeah, a common problem. Try adding a touch of Noise plug-in (like 1~3%) or Add grain for a more filmic grain.
tried the grain but we shot on HD so it wont really match if i go filmic. and the only way to get it to disappear with noise is to add so mush that it's too much.
i looked under composition setting mylenium nd i could find where to switch to 16 bpc (what is that?)
Change bit-depth in Project Settings, not Comp Settings.
i did. changed it to 16 bpc. then 32 bpc. I still get the rings
Well, even if you render internally at 32bpc, the codec you are rendering to probably only supports 8-bit.
With past projects, I've successfully busted virtually all banding with Noise at 5%. It really shouldn't take much more than that.
i am seeing it in the after effects viewer so it happens before it gets to the codec. Ill post it with 5% noise.
Even 32 bit projects will exhibit banding if your display adaptor isn't set to a high enough color depth so seeing banding in the Composition window isn't always a good indication of what will end up in the render.
I took a look at your film. You are using only about 5% of the available colors in your spot light effect. At 8 bit that only leaves about 12 steps from lightest to darkest value. You're going to get banding at 8 bit if you don't introduce noise. You either need more of a difference between light and dark, which can be achieved by adding a little hue or difference between the R G and B values, or by increasing the level of the brightest area.
Working in float (32bit), then rendering to an 8 bit codec will help distribute these bands of color but can't eliminate them unless you add a bit of noise.
Hope this helps.
The others pretty much provided all the tips. The one open question is, how you are actually combining the spotlight with your effects. There are some rare occasions where 3D spotlights well simply look rubbish, when you add adjustment layers on top of them, but that's all I could think of. Seeing how little color differentiation there is actually in your stuff, you should experience no problems at all in 16bpc. Even in 8bpc it should look much better, it's just not clear where it goes wrong.
rick, it was a black and white composition that i tinted so there were no rgb values.
I was able to get the rings to dissipate by adding a little noise and bringing the layer underneath (the boxshot) up from -100 brightness to -98.
mylenium. not sure where i went awry. no adjustment layers. spotlight.lens flare. brightness/contrast.
AE (and your display) only works with RGB, so black is actually:
and white in 8-bit / 16-bit is
R: 255 / 65536
G: 255 / 65536
B: 255 / 65536
In 8-bit, there's 255 shades of gray in each R, G and B channel between black and white. If you want a smooth transition between two similar shades of gray such as (R100, G100, B100) and (R104, G104, B104) you will only have three gray-levels, which will be visible as "banding."
If you go to 16-bit (actually AE and PS uses 15bit,) you will have 514 different levels of gray between the same two "colors."
Rick: going to 32bpc will not increase the number of "shades of gray" between black and white, and will not help this problem. The extra number of gray levels in 32-bit is used to store values below black and above white, also called HDR (High Dynamic Range.)
- Jonas Hummelstrand
thanks jonas. This has been an education.