Author Topic: Different Default Blend Behaviors (Color vs Greyscale Input)  (Read 5845 times)

I seem to be encountering a result with blends that differ depending on whether or not said blend is being used for color or greyscale output.

For example, on my screen I have a Blend node with a color texture wired into the backgound, a mask wired into the opacity, and the forground left blank.  As-is, a foreground left blank defaults to white, which is what I want for this operation. 

However, say I wire a greyscale texture into the background instead, and leave everything else the same.  What I can observe is that the empty foreground default now defaults to black instead.  See the attachment for a better understanding of what I'm talking about.

Is this the intended behavior, or is there an issue with the default behavior of one or the other?

Hi natel,

In color mode, the blend filter will use RGBA inputs. In case you have nothing connected in the foreground, you'll get a value of (0,0,0,0): a black color with opacity at 0.
In greyscale, the blend filter will have an input value of 0, so you'll get black.
That's why there is a difference :)

The blend nodes are not designed to have an empty foreground, a good solution is to use an uniform color (you can downscale its size to 32x32, no need for a big resolution), even if it's a black or white color.
Lead technical artist
gaetan.lassagne@allegorithmic.com

Ah, understood.  I'll make sure to wire in a control color at all times.