Dyeing Cotton and other Cellulose Fibres

As I have recently been working on an article for “The Journal for Weavers, Spinners & Dyers” on using natural dyes on vegetable fibres, I thought I’d write a few words on the subject here.

 There seems to be a fairly common belief that dyeing cotton and other cellulose fibres with natural dyes is often less successful than dyeing animal fibres, such as wool. This may be because some dyers use the same mordanting methods for all fibres, rather than selecting methods appropriate to each fibre type, and this can lead to disappointing results. However, using natural dyes on cellulose fibres has become simpler and less labour-intensive since aluminium acetate is now more widely available in the UK. Before the arrival of alum acetate, the alum-mordanting method generally used for best results when dyeing cotton or linen has probably been the 3-step tannin/alum/alum (or alum/tannin/alum) method, which takes several days to complete. This involves treating the fibres in sequence with both tannin and alum sulphate, the latter plus washing soda. Some dyers favour completing the tannin process first, followed by two treatments with alum and washing soda, while others prefer to carry out the tannin process between the two alum treatments. I don’t think it really matters which sequence one chooses.  Some dyers may opt to use only the alum sulphate plus washing soda step and to omit the tannin process completely, although in my experience this tends to give less satisfactory results, unless the cellulose fibres being treated have a natural tannin content, as may be the case with raffia. (See my earlier post: “A Natural Dyeing Project in Uganda”)

Detailed recipes for mordanting vegetable fibres are given in my books, so I won’t repeat them here. However, I would suggest that dyers who haven’t yet tried alum acetate as a mordant for cellulose fibres might find it worth while experimenting with the following mordanting recipe:

Use 5% alum acetate (or 2.5 tsps per 100gms/4ozs dry weight of fibres). Dissolve the alum acetate in boiling water and add this to cool water in the pot, stirring well. Then add the wetted fibres, plus more water if necessary to allow them to move freely in the solution, heat to simmering point and hold at this temperature for one hour. Then turn off the heat, leave the fibres to cool, preferably overnight, and then remove them and rinse them well. (Note: alum acetate is available from some of the suppliers listed on my blog under “Useful Websites”)

I have found this mordanting  method gives good results on cotton and other vegetable fibres. It is also suitable for silk, but not for other animal fibres, and is widely used in Japan as a mordant for silk. I used it to mordant fine silk fibres when dyeing silk for handweaver Maggie Stearn and found it most successful. (See my earlier post: “Maggie Stearn – Handweaver”)

Naturally-dyed cotton mordanted with alum acetate. Clockwise from left to right: indigo, brazilwood, weld, weld + indigo, fustic, madder, logwood, cochineal

Naturally-dyed cotton mordanted with alum acetate. Clockwise from left to right: indigo, brazilwood, weld, weld + indigo, fustic, madder, logwood, cochineal

Some of the naturally-dyed raffia fibres, dyed by the basketweavers of Rubona, Uganda.

Some of the naturally-dyed raffia fibres dyed by the basketweavers of Rubona, Uganda.

10 replies
  1. Colin
    Colin says:

    This is interesting as I have just dyed some white cotton yarn (that you gave me) with commercial dye so that I had contrasting colours for weaving. Must try some natural dyes!

  2. Ulrike
    Ulrike says:

    I dyed lots of cotton and linen fabrics last year and had wonderful results with alum acetate. In my experience there are certain plant dyes that don’t go well with either cotton or linen, independent of which mordant was used.

    happy dyeing

  3. Kathy
    Kathy says:

    Thank you for this great information on mordanting cotton. I was not familiar with using alum acetate. I can not wait to try it.

  4. Louisa
    Louisa says:

    Great information as always, Jenny! I was recently able to get some alum acetate from Maiwa in Vancouver, BC, Canada. It’s a new product for them and very pricey in comparison to aluminum sulphate. Luckily you need quite a bit less of it to mordant. Now to try it!

  5. Leena
    Leena says:

    Thank you Jenny. While I haven’t dyed anything but wool, it is anyway really good to know how to mordant and dye other fibers, too.

  6. kathyinozarks
    kathyinozarks says:

    I tried dyeing cotton with the alum. acetate per Earthues instructions last fall -and was very pleased with my results. I did mimosa, marigolds, and onion skins and the colors were all stunning-

  7. Marian
    Marian says:

    I seem to find everywhere alum sulphate and not alum acetate. I dyed cotton with logwood last year (which I had mordated with alum alongside with wool) and it looked pretty good, vibrant, but the cotton looked a bit…rough afterwards.
    I will keep looking for alum acetate!
    Thanks for the info Jenny!


    Excellent article. I use aluminium  acetate by precipitating aluminium hydroxide from alum (by adding soda) and dissolving it in dilute acetic acid for mordanting cotton.Madder is dyed a very beautiful pink with good fastness. D.M.Chaudhary, Research Chemist,
    The Ahmedabad Textile Industries Research Asoociation,Ahmedabad, INDIA

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