Matching a gold velvet to a gilded frame is not a matter of holding two gold things side by side, because gilt does not have one colour. It shifts. Under a warm bulb it goes coppery; under daylight it cools toward brass; under the cold white light of a showroom it can look almost grey at the highlights.
So we do not judge the pairing on a workshop bench. A finished gilt offcut is cut from the same batch that will finish the chair, and the velvet swatches are laid against it under the lighting the chair will actually live in. Warm-lit rooms need a velvet with more yellow in it; daylight rooms take a cooler, paler gold or the frame will look orange next to it.
We ask clients what light the chair sits in before we ask what shade of gold they want, and if they are unsure, we send the offcut and the swatches to them to look at in the room itself.
The button colour is settled the same way, last, against the chosen velvet under the same light. Buttons are small, and they are the one place a slightly wrong gold announces itself.