Gmask Edging Results Inconsistent with Trace and Soften

[kolsen]

In my continuing attempts to get less worser on Autodesk Smoke, I was fooling around with some simple connect fx compositing to get some practice with the axis nodes.

I made a simple action node, combining color planes with simple gmasks over color bars with a single light.

The edges of the gmasks are showing erratic results in both the trace and softness edge options. I have attached exported images showing the wacky results. In Sequence.01080044.jpg, notice how the edges are lightened rather than simply disappearing, and the edges of the A letter are inconsistent, with inconsistent brightness along the outer edge. In sequence.01080044 copy.jpg, notice how the edge blending over the lower dark blue and black (the results one would expect) is starkly different from the rest of the blending where the edges are lightened rather than simply gradually disappearing.

Is this a bug or a feature? Given my high capacity for operator error, is there some button I've left unchecked or unselected blend mode that will correct for these erratic results?

[joelosis]

first of all i never us trace, just adjust the softness to get your edge, from what i am seeing with ur little comp is that it is a premultiplication error, chuck a comp node in and change the alpha to premultipied, also be sure that your action setup is set to z buffer off