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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  1. Hi Barb, I’m from Vietnam and I want to thank you very very much !
    Your work is amazing, generous and a beautiful inspiration!
    My hometown is a silk fabric incubator. Our silk is very good but I think it would be more beautiful if printed by this natural method.

    1. Wow, you are very fortunate to have such access to silk, I’m envious!! Yes, there are so many eco print possibilities!! Your next step is to find good printing leaves. Have fun and experiment.

  2. Barb,
    Your posts have got me hooked and I haven’t even made a print yet! I love how well you explain things. I too am a visual learner. I feel a bit overwhelmed right now but excited as well. Do you have a book out? Thanks for sharing!!

  3. merci pour cette explication, j’ai enfin compris ce qu’est une “dyeing blanket” 🙂

  4. Thanks so much Barb for your open-ness to share details of how to experiment with using an iron blanket, so so much appreciated. I have been playing with natural dye & specifically eco-prints and just exploring making lampshades & infact printed my wool/silk yesterday then I immersed the fabric in the madder dye which ended with rich red cloth but lost the original prints …. bugger …so was looking around for how to ‘revive the prints’ … hoping after seeing your results and reading the blog that the iron blanket approach might work for me….. any specific experience/advice on how to do this given my journey thus far?

    1. There are always ways to enhance… If it’s too dark from the iron it can be lightened with a solution of citric acid or lemon juice. You can print more than once and prior iron & tannin will still react, see here It usually adds so much more detail. You may find that the leaves will displace the madder dye as that is how I use my madder, dye and then leaves Good luck

  5. Thank you very much. I maid my first steps and you help me to begin to understand 🙏�
    But I want to ask if the cotton that I use to put the leaves on (the host metirial.) should be treated also with Alum or another moderate before I cover all with the iron blanket?
    Where I live we have ekaliptus trees if it is legal to receive it from abrode.? If yes, I will be happy to send you via mail. ( Here it is not allowed to get plants from abroad if it not from official source). Thank you🍀🌿🍀

    1. I am glad it is helping! It is illegal to ship plant matter, but thanks. To print on cotton it is best to use a mordant like Aluminum Acetate. See this post where I made some myself. There are also other methods such as multiple soy milk dips or a tannin-alum sequence. Lots to learn and try!

  6. Thank you for all of your posts, photos, tutorials and blog. I am super brand new to eco printing and have not even DONE it yet but I love it so much and YOu are a big reason why it is so appealing. THANK YOU Barb!

  7. Thank you so much for all that you generously share! I have learned so much from reading your posts and your replies to others’ comments.

    When I launder an iron blanket in the washing machine with hot water after using it, does any iron remain in the cloth, and do I need to adjust the amount of iron when I use it again?

    Much appreciated,

    1. When I did repeat prints on scarves that just needed a more defined print I did notice that I got unexpected reactions from prior tannin and iron even though they had been washed quite well. I use some washing soda when I clean mine and pretend they are ‘virgin’… I have had the odd iron pattern make a print on the new fabric. I was so naive when I started I did not even wash them, I think I got interesting results since the tannins were also still coming along for the second ride. That’s when some of the most interesting things happen..

  8. Hi! I’ve been reading many of your posts and you are an abundant source of knowledge! So amazing and helpful, thank you! I was curious if you could answer a few basic questions for me. Do you have to presoak the blanket before every project you do or can you just soak it once and it can be used multiple times? Do you also rinse it after it has been soaked before using it?

    1. The blanket will get contaminated when in use as the tannins will also get on it. So I wash them well before using again just to not bring tannins into the iron water. Do not rinse off the iron water before using. The stronger the iron is the less vibrant the colours may be so experiment.

  9. You are an amazing artist and a generous teacher. I haven’t even started to print leaves yet because I am just to scared of doing it wrong so I click on your sites on Pintrest to get a little courage from your help.Thank you so much.Dina

    1. Oh thanks! If you use found fabrics and get a feeling of what works and what doesn’t is the best. Cotton (cellulose) is harder to print but easier to find super cheap.

  10. Hi Barb –
    Thank you so much for sharing your hard-won knowledge with everyone! It’s so great to find you on line with all of your eco printing wisdom. I have just ordered the supplies for eco printing with cochineal and an iron blanket, and I’m so excited to see if I can get results anywhere near yours!

    Wish me luck!