I have spun loads of natural "black" yarn and just how black that yarn is depends on all sorts of factors including; breed of sheep, genetic strain of breed, amount of sunlight the fleece has been subjected to, general weathering and probably a whole host of other factors can contribute to just how black a black sheep is.
I was looking at all my skeins of handspun black yarn together and the variation in shade from chocolate brown to almost jet black and was wondering if it was possible to over-dye something this dark, having already had success with dyeing mixed coloured fleeces. I asked around on various forums that I visit and, to be honest, not many people responded and out of those only one or two had even tried. Hmmm, ok, its up to me to just give it a go then!
I took the two black skeins from Hillcrescent Farm Jacobs Fleece No.4 and the black skein from Hillcrescent Farm Jacobs Fleece No.6 to have a go at making them a little more interesting.
I started out overdyeing the No.6 black with Greener Shades dye in Amethyst Purple at 1% dye strength but this turned out to not be strong enough and so I dyed it again at the same level of dye, effectively making it a 2% dye strength, and whilst not perfectly even coloured, the result isn't too bad and you can see the difference between undyed and dyed in the top two photos.
I then took the Double Knit weight yarn from Fleece No.4 and over-dyed that with Greener Shades dye in River Blue at a dye strength of 2% and got an all over even toned shade.
Lastly, I took the Sport weight yarn from Fleece No.4 and over-dyed that using Greener Shades dye Ruby Red, again at a 2% dye strength, for a lovely dark red yarn.
So, yes, you can over-dye something that is dark in colour as long as you use a strong dark colour at a decent dye strength. Its no good tickling it with a weak dye as you may as well throw that dye down the drain. I think that it has made these yarns a lot more interesting and prettied them up.