Well you must have been one of the ‘trendy’ people in the mid 80’s that upset the traditionalists. l’ve been around rather longer than you and remember black saddles hitting the market, l’ve never had one despite the fact, for a while there were a lot of black secondhand ones around when they became less trendy, and were consequently cheaper. I dont know if that’s still the case. These days it seems you can have any colour you want but brown would still be the choice of many people.
). Brown is a broad category, the lighter tans were always the poshest leathers, as nothing could be masked but it was, as ycbm says, a long time ago. Black was for harness as it's easier to hide faults. We now have dark and light havana, Australian nut, chocolate and myriad more browns.
I've heard it both ways, that either red dye molecules are smaller than other colours, so (at least when talking about hair!) wash out easier, or are larger so don't penetrate as deeply. So would stand to reason either way in regards to your colour wheel theory re the green!Black leather dye, like hair dye, needs all colours in it. In fact when dyeing hair from light to dark it's recommended you use a red based intermediary "filler" which can stop very dark dyes looking cold and odd. It may be that black dyes lack enough red in them, or it's simply that the red fades, green being opposite red in the colour wheel so it's often the colour that then shows up. Green or grey is most common. Brown leather simply becomes a slightly different shade of brown.
I know that's slightly short of definitive and specific but it's definitely fairly scientific
Might depend on where you were , i only ever saw brown tack as a child in Devon, My bridles came in light tan and we were told to use oil to darken over time. When i came back to riding in London on the 2000s after a long break there was black as well.
