That applies to a theoretical black, the concept if you like. Unfortunately for we modellers, and the RAF's aircraft caught in search lights, the actual paint on these aircraft did reflect some light.
The modern air show queens are lovely to see but their finish is not representative of a war time bomber at all. I posted some pictures in that other thread of a Lancaster, fresh off the production line and test flying, awaiting delivery to a unit which gives a much better idea of the finish on these aircraft.
Night was black paint, like all black paints made up from a variety of pigments. The problem is not a technical one when it comes to painting your model. It is an artistic one. As Laurie discovered, if you paint a model black it will not look at all realistic no matter how accurate the colour. You will have to apply a grey of some description. I've seen this done in various ways by various people and I can't say that one looks better than another.
It also depends on the scale of the model, the smaller the model the more grey (or less black, depending how you see it) it will need to be.
How black is this 1/72 scale He 177's lower surfaces?
I can safely say not more than 80%
Cheers
Steve