I may not  know a lot but I think  I can recognize the colour orange when I see it.  I can demonstrate:

These pumpkins and gourds are orange:

pumpkins2

Theses leaves  are orange.

leaves

So, I when I read that marigolds, when used as a dye, will invariably give a stunning shade of orange I eagerly planted a couple of rows.  Into the dye pot they went where they simmered until all the colour left them.  I put in some pre-mordanted wool and got a colour that was definitely not orange.

wool

I don’t know what you would call this colour but I think it is reminiscent of  1970’s carpeting.   Thinking that I had made some odd and isolated mistake I tried again using flowers from the same plants but a different dye pot.  I got the exact same colour.   I have no idea what went wrong.    Variations in colour is one of the interesting things about natural dyes – you just never know what you are going to get- but I understood that marigolds were one of the more predictable dyes.  Oh well, more research is required.