Here are the functions you need.

def IF(test, tv, fv): return (1-test) * fv + test * tv
def SRGB(x): return IF(Color_Step(x, .00304), 12.92 * x, 1.055 * (x ** (1/2.4)) - .055)
def ASRGB(x): return IF(Color_Step(x, .03928), x / 12.92, ((x + .055) / 1.055) ** 2.4)

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)