I've been searching over this and I don't quite get it yet. I just heard about this "z" parameter for gravitational red shifting and I thought it'd be fun to apply into the scenario of a solar-mass black hole. The equation I looked at was (1/(2GM/c^2r)^0.5) - 1 = z So, like, does the z parameter just mean that you multiply the original wavelength by it or add it with the original wavelength? Does the z give you a shift in nanometers or meters? I'd really appreciate it if someone could give me a good understanding of this.