Black light when below zero

Hey everyone
I have a problem with light emitters and emissive materials. Is there a way not to make them black with below zero intensity. I’m doing animation with f-curve noise for intensity and when it goes below zero emitters became black. not black like a black material, but visible through everything black. Or maybe the solution here is to restrict noise to go below zero…I also don’t know how to do that(without moving the whole curve).
p.s. sorry if I posted in the wrong section.