The Mysterious Iron Blanket

I am finally figuring it all out… well almost. When I first set my sights on the magic of Eco Printing I felt like I was trying to solve some crazy secret puzzle. Now, let me make it easier for you and answer one of those common questions; the Iron Blanket.

Those who had an idea how it all worked wanted to keep it to themselves, and I understand as it could be quite the commodity; like some magic recipe. Well, I feel like I am finally understanding what is happening in and around those bundles, but I would not call myself an expert either!

What is the Iron Blanket?

I get that question quite often. It is a carrier blanket that brings iron to the fabric that you are printing on. Carriers are pieces of cotton fabric or similar material (even paper towels) that will absorb the liquid solution that you’d like to combine into your combination of colour dyes and mordants and in this case it brings the iron component.

How to Make an Iron Blanket:

When I first started to ‘make’ my iron solution I used the method of soaking rusty stuff in water with/without vinegar. The problem was that it was really difficult to see how strong the concentration was. It was quite easy and did work once I had made some test runs. Buying iron sulphate is quite inexpensive and can be found in garden centres as well. It is much easier to gauge and measure for some consistency. Having said that though I still am not so fussy with exact measurements. Generally about 1 teaspoon per gallon of water is a good starting point. It’s as easy as just letting the fabric soak for a few minutes or longer before wringing out and using. Making sure the size ‘fits’ the project is also important.

How to Use an Iron Blanket:

In this above image the iron blanket is being layered above the leaves placed on the pre-dyed (cochineal) silk. The barrier (paper or plastic) will then be placed above or below to prevent ghosting through of the prints. But those are not steadfast rules as varying can make for some amazing results!

What does the Iron Blanket do?

After the processing of either simmering or steaming or my ‘alternate’ processing the unrolling is quite interesting… Notice the way that the leaves have very defined edges? As I understand that is from the tannins adhering to the metal ions and in this case it is the iron. Since the entire fabric on the right is not rich with iron it prints more around the edges where the iron and tannins meet and ‘have fun’.

There are usually pretty prints on both but quite different in style. Since the iron is absorbed into the ‘Blanket’ fabric those prints are usually quite dark and not as ‘outlined’ as the ‘host’ fabric. This allows that you can actually create 2 printed pieces at once.

I use old cotton bedsheets and often retire them to use for other purposes since they are so beautiful. This would be considered the same as only dipping the fabric in an iron solution to have the tannin rich leaves print.

Notice the difference?

The images above show the use of the same leaves however the centre ones were printed with the use of the Iron Blankets. I increased the concentration as some are quite boldly outlined. The outer samples were printed with the same processing however the leaves were just dipped in the iron solution (no ‘blanket’ used).

In this case the dye colour actually printed back from the main fabric to create some lovely details on the Iron Blanket. Often multiple use will also give them much depth.

So many…

After having printed so many (yes I am a bit obsessed when I am determined) I amassed so many in varying tones. That gave me the idea to use them in a quilt. I understand that iron (especially overuse) can degrade the fabric over time but I still wonder if we are talking 50 or 100 hundred years?!

Make something with the Iron Blankets!

The variety of patterns was easy to work with as the colours seem to be made to compliment each other. This Art Quilt brings nature in with the most unique fabric prints.

Some up-cycling of leather combines with more of the ‘Iron Blankets’ to make some Eco Printed Journal Covers. Once used the blankets can be washed and used again and again building up darker prints.

I hope I have the mystery for you and have opened up your world of Eco Printing! I am open to any suggestions or comments in this evolving art form.

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93 Comments

  1. Thank you. It’s so nice of you to offer an explanation. I have been reading your posts and thought at some point I would have to Google what the heck an iron blanket is! I appreciate your being so generous with your processes and knowledge.

    1. Thank so much Barb for explaining the process of using the iron blanket. I have experimented and some prints are beautiful and others not. But learning as I go along.

  2. Barb, your Eco Prints on fabric are not only beautiful but fascinating as well. The possibilities for design seem endless. The iron blanket made the process easier to wrap my mind around. Thank you!

  3. Thanks again Barb. I haven’t been printing at all for many months as I was getting discouraged with the results via the iron blanket issues. Thanks to you I think I’ll go back to it and see what happens. It’s -20 so no leaves at this point but lots of dried ones in between books. Hope they work.

    1. Yes, I know the -20 here too. I have stock piled my leaves from the summer and fall and re-hydrate them prior to using and they work. My first prints were quite awful too. The leaves from roses work well too, if you can hook up with a florist for her cast-offs….

      1. Barb

        Thank you for inspiring me! I haven’t tried anything yet, but just getting a place set up and my supplies that you are suggesting. How do you stock pile your leaves? I am friends with a florist so I hope she will share some leaves with me after I get started.

        1. Ferns print well too. My very first print I did was with florist cast offs. As Barb said, rose leaves do well. Blossoms were a disappointment. Daisy greens are great! Have fun!

        2. I so appreciate your posts, Barb. I love to experiment too, but you are always way ahead of me! Thanks for sharing so much of what works! Question: do you use the iron blanket formula of 1 teaspoon iron sulfate to 1 gallon water for your myrobalan printing? Not sure if it needs to be stronger. Thanks☺️

        1. Yes, that’s right. It should be quite weak though and any natural dye that is PH sensitive may get affected. Cochineal and Logwood react to changes in PH. I use a PH neutral soap to wash afterward. Iron can degrade matter over time but not sure how many years that is!

          1. I have a piece of cotton (half a metre)l did rust and tannic experiments on, in Uni in the mid 90’s…never really liked it as it felt rough, but…l never throw anything away! It is still pretty much the same as it was 25+years ago, but has been in a samples book, then in a plastic box with other samples, in cupboards etc, so may deteriorate more if exposed to air and light. As far as l recall we did not neutralise it, just air-dryed. Thank you for your generous sharing😊 it annoys me when people are secretive over their methods. Of course they have a living to make from their art, (workshops etc),but each persons work reflects their individual talent, (?) and there is room for everyone to partake. In my experience, very few people rush out and make money over someone elses work in the dye community! Thank you again👍

          2. Thanks! It’s actually funny that just today I found some of my pictures stolen and some offshore company is using the pictures to sell their products which really can’t be mine.. So infuriating! I’m not sure about it’s longevity, but so far so good…

  4. Thanks, so much, Barb! Somehow, knowing both the ‘how’ & ‘why’ can make such a huge difference, for me!I’ve not yet tried any of your projects, because apartment living can present certain challenges I’ve not been up to dealing with. But, we’re moving to our own home in a couple weeks, and spring is just around the corner, and I can’t wait to get started!
    Do you have suggestions as to other items to use for the print, than leaves? Like florals, maybe? Or do they not stand up to the process?
    Thanks again!

    1. I have not tried florals other than some one paper Generally flowers tend to be fugitive, but you may be able to get some cast-offs from sources like a florist or similar. Be prepared to embrace whatever prints you get when just learning… It will make for good experience and make you strive for better.

    2. Greetings Barb,

      Thanks so much for sharing your experiences re Iron blanket. I have spent some time experimenting with varying strengths of iron water and iron pieces in the dyepot sometimes with very dramatic but overly dark results. (Iron can really overpower bright colours). I do love the black outline that Iron gives so I’m very keen to control it better and will try your recipe.
      I hear that Irit Dulman uses the iron blanket technique. Did you learn it at a workshop with her?

      1. Thanks! Iron is quite a ‘player’ in this game isn’t it?! The iron blanket has been around quite a while, not sure who ‘invented’ it! I know Irit likes to claim the method where the blankets are switched and instead the blanket is soaked in tannin like myrobalan. The fabric is dipped in the iron instead. I’ll be showing this soon… There’s no rules! whatever works for you!

        1. I’m really only getting started in this world of eco printing and have started working through all of your older blogs. I apologize for being too literal having come from scientific work into art but what is meant by “the method where the blankets are switched”? Do you actually switch the location of the now tannin soaked blanket to the bottom and have the now iron soaked fabric on top? Or is it just the switching of which is soaked in tannin and which in iron with the layering staying the original way? Thanks for your patience! All is appreciated.

          1. Yes, different results come from whether the leaves are right side up vein side, tannin on fabric or blanket, iron on blanket or fabric… It’s fun to experiment… See here for a different look, and more in the works.

        2. I’m so lost! Do I soak ‘blanket’ in iron mordant; then soak my fabric in alum mordant and layer with plant materials – plastic sheeting/fabric/plant/blanket. Roll up, tie and steam with plain water? Do I do as above except I don’t soak fabric in alum but use the alum mordant as my steaming water?

          So sorry, I really need directions in Noddy-language!
          Regards JT

          1. Preparing the type of fibre with e proper mordant (alum for silk) is done before printing. Rinse the fabric then place the foliage and cover with iron blanket. To stop belled through images you can use a barrier like plastic, parchment or even other fabric. It’s a personal preference. I have lately steamed in my microwave There are many variations, and testing is the best way to see how your supplies work. Don’t fret, it’s fun and unpredictable…

  5. Excellent. well done for these lovely prints. I spent a couple of weeks solidly experimenting about 18 months ago and got quite far, working on silk (i found a roll in the barn…it happens in France!!!!….) and cotton and some linen too. I really want to have a go on a wool Blazer/Jacket, but dont want to ruin it. This may give me the push to try. Does wool shrink? I also really want to try cochineal too. Looking forward to spring and leaf collecting again. Will keep watching…..Bx

    1. Wool may ‘felt’ as the fibres may get agitated too much or shocks in temperature can cause it. It may be a fine hand-washable wool so it could work out well. I have used pre-washed virgin wool blankets with success. I would still suggest a test of some sort even if on another fabric. Articles should also be very clean. I lie distinct prints so the folding of garments I find to be a challenge and the risk of not working. I’d rather print on fabric and then be able to design from it. Happy printing

  6. hello Barb…
    You are open my mind and my world, with your
    frank explanation.
    I’m grateful to havehave found someone who translates the deepest secrets of ecoprint….
    Very grateful….

  7. Just to say THANK YOU EVER SO MUCH for these clear explanations and time spending to write so meticulously!!! You rock!!! Immensely grateful. Best regards from Brazil. Mara

    1. I am so grateful If. found your blog and love so much of what I see you doing. Eco printing is next for me. I also really appreciate how you use what you have, it makes it all so affordable .

      1. Yes, I hate having to buy so many supplies! Being creative with what you have or find is the best! Warning; once you start to cross the line it’s hard to go back…