2016-11-25, 14:24
I really appreciate you walking me through this and will read your link.
Where I'm getting confused is why the gradient width is relevant. What if you had an image 255 pixels wide in limited color? How would you avoid banding then? What about an image 215 pixels wide? Surely the more values you have to work with (11 for your full range example vs. 7 for your limited range) the smoother your gradient can be, other than perfect scaling I suppose. It's the whole reason higher bit-depth reduces banding - more colors available mean more precision.
Full range RGB is in effect a higher bit-depth color space than limited range RGB. 255 gradations will cause less banding than 219, just like 1024 gradations is better than 255. I think banding is occurring because RGB limited isn't being correctly mapped to RGB full. The shade of grey in your limited range "3" is mapped to your full range "2," which is too dark. The interpolated grey "12" should be mapped instead.
Where I'm getting confused is why the gradient width is relevant. What if you had an image 255 pixels wide in limited color? How would you avoid banding then? What about an image 215 pixels wide? Surely the more values you have to work with (11 for your full range example vs. 7 for your limited range) the smoother your gradient can be, other than perfect scaling I suppose. It's the whole reason higher bit-depth reduces banding - more colors available mean more precision.
Full range RGB is in effect a higher bit-depth color space than limited range RGB. 255 gradations will cause less banding than 219, just like 1024 gradations is better than 255. I think banding is occurring because RGB limited isn't being correctly mapped to RGB full. The shade of grey in your limited range "3" is mapped to your full range "2," which is too dark. The interpolated grey "12" should be mapped instead.
