Not to be too elementary, but did the packaging say that it was "copper"? Its not unknown for the wrong color to be sent out, and I'd say that its also not unknown for packaging to be mislabeled.

I looked on the Jacquard Dye website, and their color chart doesn't list "copper" but my recollection that Skin Boat School sold the Jacquard brand may be incorrect...

Chestnut seems to be popular from what I've read on QUSA.

: I have a call in on this but thought I would ask meantime. I ordered some
: Copper colored acid dye. Just mixed it up following the instructions. The
: color looked OK but soft of dark in the pot. Tried it on a scrap piece of
: the nylon and it was anything but copper. It had a green cast to it. Dried
: it with a heat gun and it looked better, not good! It was a muddy color.
: No where near the reddish copper I was expecting. I put some poly on it to
: make sure and was not impressed at all.

: I finally poured it out. No way was that going on my boat. Anyone had
: anything like this happen? I kept thinking I did something wrong but I
: measured out the water and vinegar and sure I got that right. So I have to
: assume the mixture just wasn't copper.