You're right, negative values can be problematic esp. if you don't do the maths correctly (minus times minus equals plus, remember) So better avoid negative values at all.

To start with, create all your lights with a strength of 1(100%), then hook them to your main "light switch" by the four "valueOpTimes" lines as shown in my previous post.

After that you can switch all your lights on or off with your "light switch" (which, of course, is only a master dial in your control prop)

If you've come to this point and made sure that it works OK, then you can set individual lights to individual brightnesses as you wish (in the lights' individual settings). The light strength (or on/off) will still be controlled by the master dial because 10% of 100% light is 10% light, 10% of 10% light is 1% light, and 0% of all that is ALWAYS 0% light, thus, DARKNESS :)

That's the advantage of the "valueOpTimes" method because you don't have to fiddle with "valueOpDeltaAdd" numbers which are relative to the individual setting and can easily produce even negative values...

LATER:

After you've made yourself familiar with this method you can even add more "master control" dials to control groups of lights individually, e.g."all lights on left" or "all lights from above" etc.

The possibilities are endless, and it's so easy once you've understood the method. Unfortunately you can't do this directly in older Poser versions, so you must do it by directly editing the scene file as shown in my previous post. IT COULD work in Poser11 because from what I've read about it you can now also add "valueOpTimes" operators from within P11. But as said, I don't know.

Good Luck!

Karina