I’m working on a shawl for my sisters birthday. She loves red. I’ve just dyed up some gorgeous alpaca fibre. I was supposed to be going for a deep vibrant blood red. Hmmm. Pictures come out pink rather than the salmony red it actually is but you get my point I think. Clearly I messed up! I got my fibre weight wrong – serves me right for not paying attention – which completely messed up my ratios! Oh yes, I’m one of those tedious people who takes the scientific approach to dye stuffs. No longer do I slap in about this much dye for about that much of fibre and see what happens (although I do still do this sometimes because it’s fun).
What I’m talking about specifically in this case is Depth of Shade (DoS). DoS is the intensity of the desired colour you want your fibre. Strong and vibrant or something more pastel or somewhere in between? The main thing is the more dye you use the higher the DoS. So DoS is determined by the ratio of dye to fibre (I’ll do the maths stuff in a bit).
DoS is always talked about in terms of percentages so strong and vibrant will be a higher % and the more pastel you want to go the lower %. The highest DoS is 3%. A good bright colour is generally about 2% DoS. Pastels are achieved at about 0.5% or lower. Here’s my bible when it comes to DoS (ref: Deb Menz’s Color in Spinning Interweave 2005 – awesome reference book):
0.1% pale pastel
0.2% medium pastel
0.5% deep pastel
0.75% light medium
1.5% deep medium
3% very deep (intense)
But, some dyes do not exhaust themselves at >2% DoS (exhaust means when all the dye has been taken up by the fibre and the water is clear, turquoise never seems to exhaust whatever I do, magenta is another one). This means that some dyes can be used at lower % to achieve the desired colour depth. This is good to know, because, if you are like me and like to be as economical in my endeavours as possible (I won’t say cheap) it means that armed with this knowledge this saves on wasting precious dye powder and wasted water/heat and time rinsing out said precious dye down the drain from your gorgeously dyed fibre. And flushing toxic material down the drain is a no no never! Sadly there are no short cuts to knowledge with this one it will have to come with experience of the particular dyes you use (note to self: this is why we keep notes and samples).
I hope that helps? On to the science bit – you can go now if this isn’t going to interest you…
So Dos is determined by the ratio of dye to fibre in grammes or oz. So we can say that 3% DoS = 0.03g dye per 1g fibre. Alternatively, and this is the more likely scenario. “I want to dye Xg of fibre to X% DoS how much dye do I need?” You can work this out by:
Dye weight = % DoS x weight of fibre
For example, I’ve got 25g of fibre and I want a good deep red so I’m going to want a 2% DoS:
0.02 * 25g = 0.5g of dye So 0.5g of dye will produce 2% DoS on 25g of fibre. Y
ou will probably be asking how do I do this with spoons, the answer is you don’t if you want to repeat yourself and have good consistent results. I use scales for most of my dyeing. The reason is that different dyes have different densities – this is why some dye colours fill up their packaging containers more than others – you aren’t being cheated it’s just that some dyes are ‘heavier’ than others. With a spoon this means that your measurements will be off – a teaspoon of dye X will be heavier (i.e. it will contain more dye powder in a volume based measure like a teaspoon) than a teaspoon of dye y which is less dense… Put another way one teaspoon of dye X will weigh more than one teaspoon of dye Y.
I should stop now. I’ll come back to this in another post. But, you ask, what about the unred fibre, I’m going to spin it up and then dye it again, this time making sure I got my measurements right. I will let you know how it goes.