# Changing a plane's material alpha from BGE python

I want my scene to "fade in" from black when it starts up in the BGE. For that reason I have created a plane (with shadeless, diffuse black material) in front of the camera that I want to make transparent by decreasing the alpha value.

(I connected a Python script to an Always sensor so I have a function that is called every frame; from there I set the alpha.)

However, setting the alpha does not have any effect.

plane = bge.logic.getCurrentScene().objects["blackScreen"]
plane.meshes[0].materials[0].alpha = 0.0 # just an example


The plane will always be rendered in the color (including alpha!) that was set in Blender.

Why does it not work?