If you have ever seen the common copper ore Malachite it's green. Copper is only copper colored when it is close to pure. The dye must be a copper compound.
I am no expert but I am aware that dying fabrics is not for the uninitiated. If you dye two different fabrics with the same dye you can get markedly different colors.

: 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.