B&W picture is bluish-green

This is not the answer to your question, but it is an interesting historical thing about the development of colour TV.

Some 30 years ago a friend was watching old B&W reruns of The Outer Limits and thought he could see colour in the opening credit sequence - even though he was watching on a B&W TV. He wrote to the BBC techies to enquire what was going on. They replied that at the end of the B&W era TV / film techs had experimented with simulating colour by strobing the intensity at certain frequencies, which fooled the eye somehow. It worked, sort of, but then proper colour TV took off and it was not pursued.

All B&W (positive) film stock did not necessary have a completely neutral tint. The human eye will quickly adopt to this, but a film scanner will capture this tint if not properly compensated or closing the chrominance channels.

I have also seen quite a few WW2 era B&W news films in TV programs/DVDs with a distinct brownish tint, apparently for artistic purposes. If the program also contained colour news clips, the use of some brown tint was even more common, apparently to reduce the difference between colour and B&W clips, a brownish B&W clip looks like some old colour clip that has lost the blue colour during the years :-).

In SD digital luminance signal is sampled at 13.5 MHz, while the two chrominance signals are sampled both at 6.75 MHz. The B&W material should be contained in the luminance channel, while the two chrominance channels should be empty, thus maximizing the luminance throughput.

It is called 'sepia' and I can't believe that you know so much about video re-construction, but have no clue about image capture roots.