How to export black and white picture

[Robby24597467w9bz]

Hello,

After developing my picture to black and white in lightroom i want to export it to be able to have it printed.

When i export the pic it returns to it's original colour...

How can i prevent this ?

Thank you for your advice 

Robby 

[TheOriginalGC]

Have you tried using Image > Adjustments > Desaturate to remove the color?

[Robby24597467w9bz]

Not yet but i'll try this..
The original image is raw

Regards
Robby