Velvet has a direction. Run your hand one way along the pile and it goes dark; run it the other and it lifts and goes pale. On a tall back like this one, that single decision changes the colour of the whole chair, and it is made before a single button is pulled.
We set the pile running downward on the back. Light falling from above then travels along the lie of the fibres rather than against them, so the grey stays even from the crest to the seat instead of shading lighter at the top. On the seat we run the pile toward the front edge, for the same reason - it keeps the seat reading as one colour from where you stand.
The ebonised frame has its own order of work. Black shows every scuff, so the frame is polished to its final state and left to cure fully before the upholsterer is allowed near it. On a gilt chair we can touch in afterwards; on this one we would rather not have to.
Neither decision is visible as a decision. They are only visible as a chair that looks the same colour from every side of the room.