Friday, 12 May 2017

Making Leaf Contact Prints with an Iron Blanket

The arcana of the ecoprinters seem Byzantine to the facebook observer. The images they post of leaf and flower prints on silks and cottons are lovely to admire while drinking tea in front of the computer, understanding the comments exchanged below requires a bit of prior knowledge. Researching the nature of the 'iron blanket' or carrier cloth, such a thing is variously described online. Typically, it is cotton fabric that has been wrapped round pieces of rusty iron and soaked in a solution of vinegar and water for a few weeks. Some mention using paper towels to carry iron onto their fabric. I decided surely paper would go soggy and fall apart during a long soak, maybe I could take a shortcut and simply soak my piece of old cotton sheet for a couple of hours in a diluted bowl of some iron solution I have been keeping in a jar. While I have no idea how much iron was absorbed into my iron blanket (the off white fabric in the first photo), the experts aren't precise about theirs either. I suppose they had to try out what would work for them and this would just be my first trial.
Anyway, to my understanding, once created, an iron blanket the same size as the fabric you want to dye is laid flat on a non permeable sheet, such as plastic or greaseproof paper. In these photos, you can just see the edges of my greaseproof paper, aka baking parchment, lying underneath the iron blanket. The first photo shows just the iron blanket with a selection of leaves with interesting shapes, which I hoped might prevent iron from reaching the silk scarf I laid on top, giving a resist pattern. The second photo shows the silk scarf with leaves of brambles, hardy geraniums and new shoots of lycestra laid face up on top, plus a scattering of dried coreopsis and chamomile flowers, to add a bit of colour.

Rolled around a section of plastic downpipe and tied up with string, the bundle was simmered in plain water for a couple of hours, left to cool overnight, then dried for a day. Steaming seems to be the standard method, but I haven't got to grips with sorting out a trivet to hold up the bundle and the lids for my dye pots are not remotely tight fitting.

At the grand unrolling I could see at once that my iron blanket had worked. Bramble and hardy geranium leaves seem to hold iron to print their own shapes in grey on cloth and they had definitely attracted iron from the iron blanket. The random selection of leaves I had picked from the garden hoping for resist patterns had actually left pale colours.
The aquilegia leaf made the best resist effect. The cotton iron blanket is lying on the left, with the silk peeled away from it to the right of the photo. Other leaves left subtly coloured shadow shapes rather than giving any dramatic resist effects. The photo below shows a faint fern print on the washed and ironed scarf.

Though the geranium and bramble leaves had made iron prints, and the flowers had added bronze and yellowy green splotches, the general impression is muted. Even printing throughout the roll, more professional than my usual iron soaked string results, yet neither as wild a palimpsest as my original method gives, nor as crisp and clear and rich as the photos on facebook.

Lately, some beautiful green ecoprints of horse chestnut leaves have been shown online, described as being made using an iron blanket on wool. This week, seeing the horse chestnut trees in flower, I picked leaves to try making some myself, using two pieces of wool gauze. One print would be made by sandwiching leaves between the wool and an iron blanket on greaseproof paper, the other would use my old method of simply rolling the wool up round the leaves and tying it with string that had been soaked in iron solution. The first was sprayed with white vinegar, a method frequently mentioned on the facebook group, then it was simmered in water. 
The second was heated in a plant dye bath made by simmering a bunch of dried meadowsweet, with a teaspoon of soda ash to alkalinise it. I expected an olive green background from meadowsweet and iron, rather surprised to see that gingery colour when I pulled it out of the dye bath this morning and stood it in the sun to dry. The mystery of the iron blanket bundle is, of course, hidden by its greaseproof paper wrapping. Today is Wednesday. I shall be strong and leave them both til Friday before unrolling.

Hmmpf, sigh. You may as well stop reading here. The mystery of the clearcut, deep green chestnut leaf print has not been resolved. 

This morning I unrolled my meadowsweet and alkali bath bundle, which had dulled down near to the expected olive green overall colour while drying out. There were wiggly iron string prints, nice red marks from some bits of fresh madder root, the vaguest of pale green stamps from the chestnut leaves and a modest print from a young bracken frond. Even the hardy geranium leaves hadn't grabbed enough iron to make a decent print.
How about the iron blanket and vinegar bundle?
Only marginally better colour from horse chestnut leaves. Bugger all prints from acer leaves and cotinus, though these are often shown used to great effect on the photos on facebook. 
Maybe I should try steaming the bundles, or pay for one of those online courses. Or just wait til my proper dye plants have grown this summer.

Time for a bacon sandwich and a day of planting out in the garden. Perhaps I'll do some embroidery on these this evening, while the cloth is still ridged by the leaf skeletons.


  1. I don't have a huge amount of experience with bundle dyeing but I think early season leaves don't have as much colour in them. It takes time and sunshine to develop. Maybe try again later in the summer?

  2. I think you might be right. I was looking a pictures of prints done in Italy, spring must come a couple of months earlier there than here.

  3. Could u saw a piece of PVC pipe into 1 inch lengths and cover the bottom of a pot with them for a trivet? Or use a handful of kids wooden blocks? If it doesn't have to be simmered over a flame, maybe put the whole pot into a garbage bag and rubber band the top a couple of times. Live fish are bagged with rubber bands so it is airtight. They usually bag it twice or thrice for insurance tho!

    1. Thank you - that is a great plan for trivets. Only got a gas cooker, but I really should be able to do something about getting a seal with the lids on my pots :)

  4. I've been messing with iron blankets too (also iron and alum pastes, painted onto leaves.) I was interested to see how pale your blanket was - I soaked my piece of cotton in some iron water I'd made from rusty bits and vinegar, and the blanket was quite deep yellow when I used it. Had to resort to blackberry bramble leaves that had survived the winter and oak leaves I found on the ground - quite good results- nothing else yet with promise of colour until later in the season (vancouver - we had a terrible winter and slow spring.)
    Agree, not much colour from acer until the autumn

    1. I thought with the first scarf maybe I had too much iron, the leaves were very dark. Of course, that was thin silk and the second attempt was with wool, which might need a stronger iron solution. Thanks very much, well worth considering further.

    2. I have tried many recipes. On silk I've seen the best results you can get with a ferrous sulphate solution (FeSO4) 3-5% WOF + 3% Alum (you can find FeSO4 liquid with alum) dissolve everything in a glass jar. Fill a pot of water to boil the FeSO4 solution and immerse the silk and boil low for about 1 hour. Allow to cool and rinse. Dry in a shady and ventilated place.
      Sorry for my terrible English and all the best

  5. Thank you, Miguel. Your command of English is admirable and your advice is very helpful and timely, too. I was just pondering on an autumn leaf trial with an iron blanket. Best wishes, Fran

  6. One can put leaves (oak, beech? is what I have) into a container with water, tea bags (extra tannin), something rusty and just let them sit. Mine sat for two months before I used a couple to make a nearly black, very visible but slightly smudgy mark immediately . - no steaming necessary on my test item. PS type of leaf is obvious. Heavy outline. Tumeric-- be careful.. will always brighten things up... Apply with a brush or spray. Much to experiment with.