I'm getting my coloured again soon. It's a sort if reddy colour (grey roots!!). My natural colour is dark brown. The last colour I had done was a bit "solid" so I was thinking of getting low lights which I think are the opposite of highlights - am I right?? Sort of shades of colour?
Basically yes, highlights are usually blonde, low lights are brunette colours so chestnut browns or more red based colours, exactly as you said they add tone rather than blocks of colour which can sometimes look a bit Lego hair if its not a good product. Hth