Applied liver of sulfur to exposed copper
As an experiment I used liver of sulfur to apply a forced patina to the exposed copper layer to highlight the legends on the Feegle XS.
The shiny copper turned almost black. It looks very good against the white soldermask.
The all white PCB is what it looked like originally. I carefully sanded off the raised areas of the solder mask to expose the copper. Laying a piece of 1000+ grit sandpaper on a flat piece of glass is the quickest way to only sand off the raised areas.
The forced patina compared the the naturally occurring oxidation on another Feegle XS.
I will probably spray a layer of clear lacquer over the top to protect the thin oxidized layer.
