Cochineal is a substantive dye which means that it does not necessarily need a mordant, and unlike most other natural dyestuffs where you need a ratio of 100gm dyestuff to 100gm dry weight fibre, Cochineal is only 10gm dyestuff to 100gm fibre. So my first thought that it was reasonably expensive at £6 for 25gm proved to be wrong as it actually works out cheaper than Madder!
The fibres, Silk Velvet, Cotton Velvet, Scrim, Silk Gauze and Silk Chiffon were soaked overnight in warm water. The cochineal was put inside a muslin bag. The water changed colour as soon as I put the muslin bag in.
Normally I would leave the fibres in the dyebath overnight to cool down thoroughly but as the colour still looked quite strong I wanted to use it a second time. So I took the fibres out and placed them in a plastic container to cool right down before rinsing them in warm water.
As the second dyebath yielded a paler shade I decided to soak some of the pieces in an iron mordant. Unfortuantely, even a very small pinch of iron can sometimes be too much and although the fibres came out a deep purple colour they were still a lot darker than I had intended.
These are the results.
The lefthand piece in each photo is the result from the first dyebath, the middle piece is the second dyebath and at the end is the iron after-mordant piece.
For some reason the cotton velvet came out the same in the second dyebath so the lefthand side shows the first dyebath piece and on the right is the iron after-mordant piece. This cotton velvet is some I bought from Texere Yarns and for some reason I cannot iron out the creases. I did put them on the radiator to dry off - back side down - but even using a steam iron will not make the creases disappear. I am going to try soaking them again and drying in the tumble dryer to see if that works.
This must be my favourite piece of all. It's the muslin in which I had tied the Cochineal!