I would do this entirely in the color corrector, except that the saturation control appears to come last. I got around that by adding the Black & White filter in the change first, then the color corrector. Set the B&W blend amount to 1.000 to get monochrome. In the Color Corrector drag the "Low" wheel all the way towards blue and the "Mid" wheel halfway towards blue. Use the Gamma slider to adjust the lightness/darkness to your liking.

1- Conversion to B&W:
You can use the Channel mixer to convert only R, G, B, R+G, etc. into black and white.

If you want a really gritty B&W conversion, use the channel mixer trick and try to produce a B&W conversion that yields the LEAST contrast. Then use the color curves and add a very strong S-curve... this will bring back the contrast and also a lot of detail.

2- Another way to add tints is to use the gradient map filter. Pick three shades of blue that *aren't* exactly the same. At the low end use black and at the top use white.

It's a different look that you might like.

Glenn makes good points!

Reducing the saturation to 0 often does not give you a good b&w image (it looks like color photo printed in b&w, which is not the same).

There are advanced b&w film simulation plugins for AE and other platforms, and Glenn's suggestions are great for artistic use.

I would use two tracks:

Bottom track would use the B/W fx, maybe brighten it up a bit so the whites begin to pop.

Then duplicate the B/W track above. Then apply color correction as explained above, and reduce the track opacity until you get the effect you want, maybe to 25-35%.

That will give more transparency to the effect, it's similar to a very simple colorizing technique.

Of course you'll want to check your output levels lest they get too hot.

A nice clean way is add Black and white fx to clip track 1 then add a blue media gen panel underneath track 2 select blue you want and then composite add = done

If you want black to be add to the blue then drop slider on blue track = clean composite

This way you can choose the blue you want like going to the dentist and choosing which tooth you want pulled ..big big bonus

to add..........Instead of BW fx Try Brightness and Contrast fx you will get hue’s in the same tones you are using for you color comp in track 2

Thanks all for great sugestions - I'll try them out tonight :-)

/Ulf