If it is Farrow and Ball the advice from the company is to use a test pot first due to variations in colour due to light in the room etc, and not just guess from the colour card and they are quite correct! ( Yes I have used F&B several times, but not in that shade ?). But being such Interior and decorating gurus, I'm sure they knew and have done that. I am also continually gobsmacked at the " speed painting" . Guess it would make a good vlog..........any paint companies and/or decorators out there interested in a #spon? Particularly to try and cover up an BELTER of a blue wall ?