Author Topic: shape>edge artifacts>blur>PROBLEM  (Read 1100 times)

I have attached an sbs file with a simple example to this post so you can have a look at the issue for yourself.

The problem I am having is that when using shapes or svg as a mask - I am getting these dark lines appearing at the edges, they may seem like something that's not real important but as soon as I put a HQ blur node on the shape those small lines turn into big dark lines and I need a smooth transition without any dark lines.

I basically want to get a nice smooth colour gradient without the black lines. I'm not using an actual gradient as a mask because even with levels it does not give me enough control over the gradient, so this is the way I've come up with to solve that issue but it wont work if I can get rid of those dark lines.

I have also included some images for quick reference...

just showing the example graph

dark lines with no blur (only showing in 3D view, the 2D output node has no dark lines)

This shows the same again but the 3D view is zoomed in so you can see the dark lines better

This last one shows what happens when blur is applied ( both 3D view and 2D output have dark lines)

Why the 2D output doesnt have the lines before the blur and only the 3D viewport does - Then after blur they both have the lines seems a bit weird too?!

I think I have narrowed it down a bit...It seems that one reason for those line artifacts was downscaling (the mask was set to 2048 while the blend node was set to 512)

I am still getting the issue regardless; just now its something the actual blur node is doing to the image. with intensity set to 0 there are no line artifacts as soon as I put anything greater than 0 those dark line artifacts appear.

I guess I need to see if I can open it up and change something inside?!

So I managed to find a work around... (sbs attached below)  hope this helps someone

This sbs creates a custom gradient from shapes, to give more control than a standard gradient (and levels adjustment) gives over the spread of the gradient, also it improves the colour blending by using a sRGB conversion node, which gives a result similar to that of working with 32bit colour gradients.

ie. no black lines :) or weird bluring

I did attempt to change all nodes to 32bit to see if that solved the issue it didn't - I don't think designer knows how to deal with 32bit colour out of the box (I mean other than displaying a 32bit colour image- any processing is probably done in 16bit or below- which isnt an issue as long as there is a way to convert it into 32bit properly once its processed)

Anyway I'm still not happy with the smoothness of the created gradient so Im going to be working on that as well as finding a more accurate way to blend colours that is more akin to 32bit colours.
Last Edit: May 11, 2018, 03:08:14 pm

and for quick referance here is a before and after