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Doc_Pit
Doc_Pit
Inspiring
January 22, 2017
Answered

Vignette banding problem

  • January 22, 2017
  • 2 replies
  • 2513 views

This topic has been closed for replies.
Correct answer davescm

You are fine with the black background.

The known artefact shows up only when viewing a gradient mask against the transparency grid. It is not the transparency, or the mask, that is the problem it is viewing it against the chequered grid. That is what is showing as heavy banding in your first image. This is a known issue, but does not impact on the actual image - as you do not view that chequered grid in your final image.

The second and third , do not show that artefact and  are just the mild banding that you will see on an 8 bit display and a smooth gray gradient. A little noise will help with that.

Dave

2 replies

davescm
Community Expert
davescmCommunity Expert
Community Expert
January 22, 2017

I can't see the impact in your small screenshot.

However I do notice , you are showing the effect of the mask against the transparency grid. If you put a plain white layer behind the image do you still see it? There is a known issue ("bug") that shows an artefact against the transparency grid but does not impact when shown against a real layer. I suspect you may be seeing that. It is easy to check - just put a temporary plain layer behind the image. If it is that - then do not worry - it does not affect the actual image.

Dave

Benjamin Root
Benjamin Root
Legend
January 22, 2017

If you flatten the image, does the banding clear up? I can't really see any banding, although the image is rather small.

Doc_Pit
Doc_PitAuthor
Inspiring
January 22, 2017

Gentlemen, thanks very much for your responses.

Benjamin,

I'm inserting two images which, hopefully, will show the banding more clearly.  The first image shows the original.  The banding is most visible along the bottom left and running up the side.  The second two are sections of the flattened image.  There remains just a bare hint of banding in the flattened images, perhaps most visible in the last image.  It's more visible on the monitor than it is in these captures.

Davescm, I'm puzzled by your instruction. My vignette mask causes the banding, and my vignette mask is going to turn any layer below it to transparent along the edges, including any white layer.  My guess is that I'm misunderstanding you.  I have inserted a shot of my layers. Where would I insert the white layer as per your suggestion?

davescm
Community Expert
davescmCommunity ExpertCorrect answer
Community Expert
January 22, 2017

You are fine with the black background.

The known artefact shows up only when viewing a gradient mask against the transparency grid. It is not the transparency, or the mask, that is the problem it is viewing it against the chequered grid. That is what is showing as heavy banding in your first image. This is a known issue, but does not impact on the actual image - as you do not view that chequered grid in your final image.

The second and third , do not show that artefact and  are just the mild banding that you will see on an 8 bit display and a smooth gray gradient. A little noise will help with that.

Dave

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