First things first -- you have to go see bagginsbill's new Clouds background shader. That's really something. Puts my little toy in the shade!

Anyway, I applied my toy shader to a curved background prop that came with a light set that I bought (in my early Poser days) and it came out upside down. I had to invert the gradient and set the V-Pos to around 4.0 to get the transition in the right place on that background prop.

I haven't tried it on a standard hi res square yet.

To flip the gradient, just bypass the math subtract node that inverts the "V-Texture-Coordinate" node. I'm going to add another parameter to control this.

Okay, okay, I admit it.... I just enjoy playing with nodes.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)