WB Before and After shooting - RAW

Iliah Borg wrote:

Ok, so with the black image now downloaded, do I use that as my white
balance by putting it on my memory card and using that preset in my
D3x?

Yes.

Secondly, about the curves, my neutral setting already seems to have
a linear setting (the line is straight from bottom left to top right
already) I take it that I can therefore use that setting?

It is showing like that, but you need to go through the the custom
curve mechanism to load a true linear one into the camera.

I do not believe something can possibly replace a hand-held meter. I
use UniWB mostly not to have a premature warning of blown-out red and
blue channels, and for consistency of the images, especially when
using colour lights or colour filters.

Thanks Iliah,

This thread has been both interesting and helpful, you use the histogram for the same reasons as me, when shooting landscapes at twilight hours the camera's auto white balance will often give a strong blue cast (like film would without the use of filters) and therefore the histogram will report a blown out blue channel prematurely, this method will help fix this issue.