Are you seeing this in your final output on the video monitor? Or is it just in the Composition panel on your computer screen? If you haven't already done so, do a test output and watch it on the final viewing device (i.e., a video monitor / television).
I concur with Todd. Do a test first. If it's just inside AE, then there may be some issue with your graphics driver or OpenGL. Also try using the Circle effect as an alternative. Under some conditions masks will always cause odd blending du to rendering order and how e.g. channel effects may modify transparencies...
Ah yes, good point.
It was on the PC monitor and video monitor. I have just rendered it and looked at it as a final product and it does look better. Still banded though.
So 2 new questions spring to mind
Can I improve it further? Is that where 16bpc come in? But then I guess once it goes to digibeta tape it will be back to how it is now.
And is there anything I can do to make my preview on the broadcast monitor look closer to the end result? I guess a combination of AE render settings, GFX card and driver. Is this right?
And thanks for your reply.
I tried a few different ways of acheiving the gradient with similar results.
I can probably get the engineer to look at the difference between preview and final render, but I'm interested in if there is an inherent issue here with PAL and 8bpc.
You can improve it further by adding just a little bit of noise. 8bpc is such a low bit depth that a gradient between two similar colors is almost inevitably going to show banding. That's why dithering was invented. Dithering is the introduction of a little bit of noise in the colors.
Thx Todd. That's very good to know, I hadn't realised that's where dithering came from.
Interestingly I had tried Sapphire's Gradient effect earlier and fiddled with the noise parameter - I was just curious, thought it'd look awful but it really did help. I had never heard of that tactic before.
I think I'm going to go with a solid colour now anyway but thanks so much for the knowledge. Useful stuff