Annatto is most commonly used today to dye foods rather than textiles. In fact, it is responsible for the classic orange colour in American cheddar cheeses, and that bright hue can also be applied to textile fibres.
Bixa orellana, known as annatto in English (roucou in French, and orlean in German and Dutch), is native to Central America. It has historically been used as a dye in the Americas, with evidence of its use spanning back to ancient Peruvian graves. It entered the European market at the close of the 16th century. It never became an economically important dye, however, although it did have home use. While easy to use, annatto is not particularly lightfast, and like orcein dyes, has a history of being outlawed by dyer’s guilds.
The main chromatophoric (coloured) chemical component of annatto is bixin, which is isolated from the small fruits of the tropical shrub. Depending on the concentration, mordant, textile makeup, and length of dye, the colour can range from orange to red. One such colour, typically used on silk, was known as aurora or morning red, and evokes the brilliance that can be obtained.
Always wanting to try my own hand at things, I took it upon myself to dye some blue-faced Leicester (BFL) wool yarn that I had previously spun on my handy top whorl drop spindle. I used whole annatto seeds and an alum mordant. While annatto can be used as a direct dye, that is one without the chemical binder known as a mordant, it is possible that the use of alum can provide a more even distribution and better colourfastness. It also appears that annatto, like many dyes, was fermented before use in the past, but I believe my seeds were simply dried.
Recipe and Procedure
2 skeins BFL handspun yarn, totalling 160 g, mordanted with 15% weight of fibre (WOF) alum and 8% WOF cream of tartar (done by these methods).
100 g whole annatto seeds
Tap water (unknown pH, from a soft water source)
First, I brought 100g of whole annatto seeds in water up to a gentle simmer. After just over an hour of hovering between 90-100°C, I let it cool slightly and strained the seeds out. I returned the dye liquor to the bath, added enough water to fully cover my yarn, and added two skeins of still-wet alum mordanted fibre.
After a low simmer for about an hour, I was dissatisfied with the depth of colour, despite having read that a 1:2 dyestuff to fibre weight was adequate. I decided to grind up the annatto berries, place them in a pantyhose foot, and return them to the dye bath with the yarn. While this may have contributed to unevenness of colour, I found it to create a much deeper shade. I tried to gently turn the fibres throughout the process, but still ended up with darker areas. Which looks nice, so no worries there.
I let the dye liquor and yarn barely simmer for about three hours, then killed the heat and let the yarn sit for another 4 hours, turning occasionally.
Afterwards, I did the usual rinsing, adding a small amount of soap to the rinse to encourage out any excess dye.
Not wanting to waste anything, and curious about the result, I did a cold exhaust dip dye on another 80g skein of handspun BFL. This was a simple procedure, which just involved taking the remaining liquor, pouring it into a pickle jar, and placing one end of a dampened alum mordanted skein (15% WOF alum 8% WOF cream of tartar) in it. I left it for about 10 hours before removing and rinsing.
The colour is pretty lovely, and in the future if I dye with annatto I will grind the seeds up right off the bat to ensure that more of the bixin is released into the dye liquor. My main concerns, however, are about light fastness, which unfortunately I only discovered after my dyeing was already underway.
The exhaust bath created a pleasant, if very mild creamy orange. I will play around with this skein more and see what colourway I can come up with.
Sources and Further Reading
Maiwa Guide to Natural Dyes http://maiwahandprints.blogspot.co.uk/p/guide-to-natural-dyes.html
Grackle & Sun: Dye Day #1 Results: Annatto Seeds https://grackleandsun.wordpress.com/2012/07/09/dye-day-1-results-annatto-seeds/
Hofenk de Graaf, J. A. Natural Dyestuffs: Origin, Chemical Constitution, Identification. International Council of Museums Committee for Conservation (ICOM CC) September 15-19 1969, Amsterdam: Central Research Laboratory for Objects of Art and Science