Friday, 11 August 2017

Contact Printing a Cotton T Shirt with Dye Plants

The project for August in the Dye Plant Calendar 2017 is contact printing with fresh dye plants. Half a page summarises an essentially simple process, though I have come to realise there is a great deal more one could usefully say about all the monthly projects. 
Following chat online about ecobundles, I understand there are a great many methods suited to different plant materials and different print effects. I enjoy the gardening aspect of plant dyeing so the process I've developed is essentially making freshly picked dye plants, the classic kind that contain intense concentrations of dye, print with their own dye.

Over the years, I've blogged about various successes and failures trying this and that with plant prints. At the risk of becoming monumentally dull, this particular blog will be a (very) detailed description of what I am currently doing to make prints like the one on the T shirt shown above. I'd hesitate to call it 'ecobundle'. Maybe I should be explicit, the process doesn't use vinegar or soy milk or iron blankets and does rely on the cotton being treated first with a chemical mordant, aluminium acetate, which I buy from Wild Colours online shop. This is not the same stuff as alum, which is only a mordant for protein fibres like wool and silk. I use aluminium acetate because it is a straightforward, fairly quick, one step treatment for plant derived fabrics like cotton and linen, it does not add any colour of its own, but does reliably enable the adjective plant dyes to fix on and stay bright, rather than fading fast.

Since this is intended to be an exhaustively thorough reference blog which will save me giving lengthy explanations in future, I will add, though I expect this is obvious anyway, when you are mordanting and dyeing with plants, do not use kitchen equipment you intend to use for food and while working, take safety precautions, bearing in mind that dye plants themselves may be toxic or allergenic and aluminium acetate, iron and copper are none of them fit to eat. 

I'm no seamstress, so I begin by buying a 100% cotton T shirt (second hand, of course). The thread used to sew them together is usually polycotton which doesn't take up plant dyes well, so I have to live with any visible stitching remaining undyed. An accurate weighing scale is ideal, if you don't have one, to give you a rough idea, a cotton jersey women's medium size of decent quality and thickness would weigh about 140g. To clean off or scour the fabric, my T shirts go through a 60 degree centigrade wash cycle with no powder or conditioner in the washing machine, though you could equally well thump one about in hot water by hand. While it is washing, I weigh out 5% of the weight of the T Shirt in aluminium acetate, which is a fine white powder, one heaped teaspoon is about the 7g needed to mordant a 140g T shirt.

Put the aluminium acetate in a jam jar, pour in hot water, stir well and leave to stand. Fill a large pot, at least 10 litres capacity, with warm water and stir in the dissolved aluminium acetate. Now add your T shirt, still wet from the wash, squeeze out any trapped air pockets, bring the pot to the boil, simmer for an hour and leave to cool. Give the fabric one rinse in plain water and either use it straight away or dry it to dye later. There will still be half of the aluminium acetate left in the pot, so you can save the fluid or just add another 3.5g (half a heaped teaspoon) to mordant another T shirt.

In the meantime, make a plant dye bath to give colour to the parts of the T Shirt that are not included in the print roll. I often use the afterbath of a plant dye bath that has already dyed some wool. Otherwise, I pick whatever flowers are plentiful - August is a great month for yellow cosmos, coreopsis and Dyer's Chamomile, earlier in the summer I'd go for meadowsweet - and just put them in the dye pot with water, so they can release their dye while the printing bundle is simmering. Adding a bit of brown onion skin peps up the orange and yellow tones. To my mind, the resulting uneven, splotchy background rather suits these prints. 

Here is a table set up with my contact print equipment. One aluminium acetate mordanted, soaking wet cotton T shirt. One section of sawn off plastic drainpipe 26cm long (a little less than the width of my dye pot). A ball of undyed cotton string. Four mugs. A roll of greaseproof paper (aka baking parchment). A jar in which rusty nails have been dissolving iron into a mixture of water and vinegar and a similar jar with dissolving bits of copper piping.
Vinegar contains acetic acid. This will dissolve rust, which is iron oxide, to make iron acetate. It will also dissolve copper oxide to make copper acetate, though much more slowly. If you can't wait for weeks, you can buy ferrous sulphate and copper sulphate as crystals which dissolve instantly, but read up on safe handling, because metal sulphates are more toxic than homebrewed acetate solutions.

Unlike fine silk, cotton jersey is thick enough to prevent plant dyes from penetrating cleanly right through. The prints will be much clearer on the side of the fabric touching the plants, so turn the T shirt inside out. Some dye will pass through the fabric, so the next step is to keep the plant prints distinct and prevent the colour from the main dye bath reaching the printed area.
Tear off a length of greaseproof paper a little wider than the T shirt and as deep as the section of pipe, or the stick, or whatever you will be rolling your T shirt around. Lay the inside out T shirt front side down over the strip of paper. Now put two cups in through the sleeves and two at the bottom opening to open some space to work inside the T shirt.

Hooray, at last you can skip around the garden, harvesting dye plants. The ones that I have found contain intense concentrations of dye sufficient to print their colour and shape directly are the flowering spikes, stems and leaves of weld and coreopsis tinctoria and madder roots. Double maroon hollyhocks, yellow cosmos and Dyer's Chamomile will make blotches of colour, though they are unreliable at making recognisable flower shapes.
Dip the weld flower spikes and leaves in the iron solution, shake off the excess fluid and lay them inside the T shirt where you want them to print. The small amount of iron will modify their natural yellow luteolin dye into green, which shows up better, in my opinion. You could do the same with the Dyer's Chamomile flowers.
Lay the sprigs of coreopsis tinctoria inside, just as they are. The dark red flowers give a dusky halo round the orange print of the centres, the petals with more yellow don't always show up. Coreopsis leaves wilt within minutes, so lay them in before they flop, because the prints they make are beautifully crisp.
Thick madder roots can be chopped up to make a sprinkling of little red dots on the cotton, though I think the fine wriggly roots are used to their best for making contact dye prints. I lay on the splodge plants last - you can see one double magenta hollyhock and yellow cosmos on the top layer, the cosmos flowers get a dip in the copper solution to bring up their colour.
Take out the cups and gently straighten out the T shirt, ready to roll the working area with the plants inside and the greaseproof paper underneath, like a Swiss Roll, round and round the pipe, then bind it firmly over the outermost layer of paper with lots of string.

Here's a good video for learning one handed, quick release knots.
Submerge the roll slowly into the dye pot, making sure the water flows inside the pipe so it won't bob to the surface. Bring to a low boil and simmer for a couple of hours, then leave it overnight. Thick aluminium pots are harder to clean than stainless steel, their advantage is that they keep the heat for hours longer. I buy mine second hand on eBay. You could keep an eye out for anything 28cm wide or bigger, between £20 - £30 per pot including p&p is pretty good, they do last forever. 

Anyway, here is the roll in the pictures above, which I pulled out of the pot to drain this morning. Impatient as I am, I know that if I unroll it and wash it too soon, the prints will be paler. I shall give it a few days to dry slowly, then a few more days after unrolling to fix before I wash it in the machine at 30 degrees centigrade with a pH neutral detergent and finally give it a hot steam iron. 

Here are some I made earlier. It's a gloomy morning for taking glamour shots and they look considerably more vibrant in real life. I nobly resisted the temptation to use the enhance function on this photo - it annoys the tits off me when I can tell other people have done that. Last question, will these prints last? I can say with confidence that if I have a flower dyed T shirt displayed in the shop window of Crafts by the Sea, exposed to full sun every afternoon, the colours will dim considerably over the course of the summer. The ones I keep in a drawer to wear and wash myself are good for years. Shirts made of cotton and linen blend take plant dyes even better. Here's one I filled with plants before folding it up to roll around the pipe. It was photographed on a brighter day, you can come and have a look at the real things if you happen to be passing through Ogmore by Sea. The shirt's in the shop for £30, the T shirts will be taken down there on Sunday and will be for sale at £20 each.


  1. Beautiful art again! Is the Calendar still for sale? Are u going to do another Calendar for 2018? I'm planning my Xmas present early. I don't mind if the Calendar has 2017's dates on it, or if it is available as an ebook. Sorry I haven't been commenting much I have been so busy but I have been watching from Australia

    1. I am just starting to get my head round writing an improved calendar for 2018 - with 2018 dates :) There will be different pictures and some different projects, though not twelve completely new ones. I was thinking of sticking to the original idea of keeping the calendar instructions short and sweet, but offering an ebook companion which expands on all the other things that could be said about each monthly project. I really appreciate your encouragement :) Have you got lots of eucalyptus?

    2. Great! I'm interested in both the calendar and the ebook then. Definately would like the Calendar in the same concise info way of this year and then an expanded volume, I love your projects. Lots of eucalyptus around at the local park and apparently America has it there as well. There's some bottlebrush on my street and I've been squashing various plants between my fingers to see if they give off any colour!

  2. Wow - those T shirts are beautiful. I'm buying some Aluminium Acetate right now in order to try this.

  3. Great commentry Fran and beautiful tee-shirts.

  4. Spelling error oops, commentary!

  5. Great tutorial, lovely shirts! Thanks for this.

  6. nice results - the red roots look like bows in your flowers:) I just picked a few seed pods of nz flax and remembered that they give lovely brown dyes on wool and silk... they look like vanilla pods, but split up into three or four fingers, when ripe - might be nice for eco printing as well? they should be around to pick now...

    1. NZ flax pods ... sound like a great shape to print with. Best of luck :)