Softimage Xsi: gradient change of toon ink with z depth

hello everyone,

I am currently working on a toon shaded scene set out to sea.


i would like to change the ink colour on the lens shader from black in the foreground fading to a lighter colour at the hazy horizon.


I have tried various setups in the render tree with falloff nodes, mixers and boolean nodes in bypass and spread etc........but to no avail.

In short i have been looking at it too long.


Can anyone help me out with the solution to this teaser.


The closest I came to the desired look was to connect a linear falloff node through a boolean to the bypass of the lens. This was ok but had strange regular spaced notches in the horizon ink????which was a little odd.


please help.

cheers

bigmuff