Variable Blur not working?

So, I try to use Variable Blur in combination with a black and white gradient. But it will only blur for the white value over the whole thing. The blur value for black gets ignored completely.

I had some other problems with Gaussian Blur not working. But that does not have to be connected.
(Radial works fine, tho)

Some suggestions?


Hi Caracan,

Can you post screen shots?

There really isn’t enough information in your description to understand what you are working with.

I put together some objects that included 100% white, 100% black and a 70% B/W gradient as well as a color version. I moved the objects around to various scene and layer order positions and adjusted the black and white values in the Blur-Variable node. I am seeing both the black and white values reflected in the rendered results.

Hi Ampy.
Thanks for your answer.

I got it working. Adam suggested I should try transparency for the black value, so alpha of 0. That worked.

The problem is, when I have a gradient (drawing layer) from 255/255/255 white to 0/0/0 black (full colour would mean 255 alpha), and I want to use that gradient as matte for the variable blur to get f.e. blurring of 2 for white and 20 for black. So less blurred where white is to gradual heavier blurred where black is. (It says black in the properties of variable blur after all)

  • this configuration does not work, because the blur just uses the value of 2 over the whole gradient.

I guess, it is the alpha not the colour value that is essential here. It would make sense to specify here that black is supposed to mean 0/0/0/0. Which is not the case whenever you work with colours in a layered system and you need black to be fully opaque.


Adam = solution of course :slight_smile: Glad you got it sorted out.