Compare Basic Eco Printing Methods

You are probably here because you want to join in on the Eco Printing ‘magic’?! You’ve seen that amazing art utilizing botanical leaves to permanently print on fabric. Let me offer you a bit of help to understand some of the different basic Eco printing methods.

This post tests different Cellulose fabrics with and without a mordant (aluminum acetate) and also use various methods of printing. We must understand that even though there are techniques used there still are many variations that will have an impact on the outcome. The basic understanding can be beneficial when deciding how you will print. I will also be using iron mordant (in the form of Ferrous Sulphate) to keep these prints quite simple.

Making my Own Aluminum Acetate:

I’d rather not buy chemicals so my understanding is that Aluminum Acetate is a mix of Sodium Acetate and Alum (aluminum potassium sulphate). Sodium Acetate can be made at home with baking soda and vinegar. In my test I used 1 litre of white vinegar (5%) and slowly added baking soda (sodium bicarbonate) stirring carefully until it did not fizz anymore. Be careful to have a vessel that will accommodate the extra volume during fizzing.

The amount I used of baking soda was about 88 grams in one litre of vinegar. This reaction creates carbon dioxide, water and sodium acetate. The sodium acetate is however still dissolved in the water but for our use that is fine, the CO2 goes up in the air. The amount of sodium acetate made would be slightly less than the amount of baking soda used (from what I have researched), as this calculation is above my non-chemist ability.

In my case I estimated that there was 85 grams of Sodium Acetate in the water and then I added the same amount; 85 grams of Alum (dissolved in warm water) to it (making 170 grams of Aluminum Acetate). Make sure the bucket can add the 5 litres of hot water. The weight of fibre (WOF) that 170 grams of Aluminum Acetate can mordant is 2125 grams of fibre ( 8% Aluminum Acetate mordant/WOF) After letting it soak overnight, rinsing and drying I was set to go with comparing mordanted to un-mordanted cellulose fabrics.

Comparing Fabrics:

To compare how the fabrics behaved I used well scoured (cleaned) linen (vintage), cotton sheeting (vintage), cotton twill and cotton t-shirting. These are all cellulose fibres which are more difficult to print than on protein fibres (silk, wool ) I made a code of each technique to keep it all straight…

  • Use of ‘Iron Blanket’ (IB)
  • Fabric Dipped in ‘Iron Water’ (ID)
  • Leaves Dipped in ‘Iron Water’ (LD)
  • Both Methods ‘Iron Blanket’ & ‘Iron Dipped’

Each method was also tested across the different fabrics and the mordanted and un-mordanted versions

Simple Eco Printing Tools:

I have a pretty large collection of leaves that have been pressed, dried and kept in clear containers for later printing. I also have access to some very well printing (tannin rich) fresh leaves of species like silver maple, sumac, black walnut, cotinus, black locust, purple leaf weigela, japanese maple leaves, to name a few.

The dowels used to bundle on are old wood curtain rods. I reuse the plastic strips as a barrier to stop any ghosting/bleed of the leaf prints going through the fabric layers. I use a painters drop cloth instead of plastic wrap but you can use whatever barrier you’d like. Since I process my prints in the microwave oven I also reuse the bags that the bundle steams in. The butchers twine is rewrapped onto the spool so I never need to buy more or deal with tangles. The system I use makes it easy to get a few bundles done without a huge inconvenience…

The Iron Blanket Method:

Once I deciphered what this mystery was this is one of my favourite techniques of eco printing. It is a good place to start for a beginner using up-cycle cotton fabric. The fabric that I find works great as an iron blanket is well used cotton flannel (washed many times). The amount of iron sulphate powder in the bucket of iron water is variable. I do like strong definition so I tend to be ‘heavy’ on the use of iron – 2 teaspoons/bucket, but experimenting will help you find your preference. The amount of fabric (WOF) will also play a role when you iron dip and see the orange colour just disappear into the fabric. You can also make iron water with rusty nails & water (& vinegar)

The Leaves:

When I use the dried leaves from the past years I quickly re-hydate them using hot water with a bit of iron sulphate if desired or plain. I soak only for a couple minutes as I do not want the leaf to lose it’s tannins and react too much with the iron. Pour out the excess and place leaves on a towel to soak up excess moisture.

Layers; Cotton fabric, leaves, iron blanket, barrier rolled tightly on a thick dowel.

Bundling the Eco Print:

An important part of the process is making sure that the bundle is quite tightly rolled and there is good connection between the components, the leaves fabric and iron blanket if using. The barrier is a re-used strip that will keep prints from bleeding through but you can omit of you like. Once rolled string is wrapped tightly at small intervals to give good pressure. My method of using a dowel of string works well for me.

See the different methods below to observe how it affects the outcome; then you can decide what look you may find appealing.

Method: Iron Blanket

This cotton sheeting (mordanted with Aluminum Acetate) was dried and then rewetted before placement of the leaves. Notice the leaves, plant material (silver maple, cotinus, walnut japanese maple & sumac) are vein side down. A separate flannel sheet (iron blanket) was dipped in a ferrous sulphate solution (about 2 teaspoons Ferrous Sulphate in 7 litres of water) wrung out and then layered on top, and a barrier layer on top of that (see image above)

After processing (steamed in a re-used plastic bag) in the microwave and unrolled, this is what the result looks like; notice the way the edges are defined with a bit of an outline. Some of the iron does react with the leaf tannin to give each specie’s characteristic and some colour.

After washing and drying this the final print. Do notice there is still some yellow from the use of alum in the mordant. Compare to the following methods…

Method: No Mordant (AA) Iron Blanket

To make a comparison this the same as above but without the use of the mordant. I’ve used the sam fabric, leaves, iron blanket, barrier and bundling.

After the processing in the microwave and unrolled this is the result prior to washing. Again, notice the distinct definition around the leaf prints. A small amount of print shows through the shape of each leaf. After making test prints with the foliage that you have available you will build a list of good printers.

After washing this is how this cotton fabric looks. As you may notice there is less yellow colour to the print but still the definition of the edges. The iron (from the iron blanket) reacts with the tannin, especially at the edges.

Method: Iron Dipped Fabric

Still using iron, this cotton twill fabric is dipped (and wrung out) prior to placing the same species of leaves. Now the iron is available to all parts of the leaf since it is in the fabric and no Aluminum Acetate was used. There is no ‘blanket used but a plastic barrier layer, processed again in the microwave.

After unrolling there is much more noticeable dark prints since the tannins have reacted to the iron mordant. The fabric has also taken on a more rusty colour.

After washing and drying some of the rust colour has left but the leaf prints are still quite dark. Varying the amount of iron will yield different shades but will also ‘sadden’ the colours of that leaf.

Combined Methods: Iron Blanket & Iron Dipped

It donned on me that many use only one of the options above but why not both? You don’t learn until you try… I used a cotton twill that has been mordanted with aluminum acetate and the same leaf species, some being placed with the vein side up.

After processing and unrolling, there are quite interesting results. As I expected there is a combination of results similar to above tests. There are definitions around the leaf edges as well as dark prints of the vein sides of the leaves. Personally I like the look of this and varying the strengths could be quite interesting.

After washing some of the rustiness has washed out but details are still strong. I do like creating interesting designs by using either sides of the leaves.

Leaves dipped in Iron:

Another method to bring iron into the process is by dipping the leaves in ferrous sulphate solution. I used some dried leaves that have been rehydrated in the warm solution and placed on the aluminum acetate mordanted cotton twill fabric.

After processing (steam) in the microwave the prints are quite strong. The colours of fall leaves are making quite strong golden colour prints. Learning what colour a leaf yields after processing is key. The amount of iron will ‘sadden’ the hues of colour but some metal mordant tends to produce defined prints.

After washing the prints become somewhat cleaner. Do you notice how the dark red leaves actually printed a green colour. This is the lovely mystery of eco printing. Try not to have huge expectations and do take notes.

Iron Dipped Cotton Fabric

Really simple, no prior mordant other than dipped in iron sulphate solution. This may be easy but not every leaf has the potential to print, do not be fooled that the leaf colour will be your result in most cases. My knowledge has grown from testing and trying and testing some more…

After washing and drying the details are strong but quite grey. It all depends what you desire, I often do like monochromatic prints. I hope this tutorial has shed some light on this mysterious eco printing, making art with botanical prints.

The possibilities are endless when you vary fiber, mordants, natural dyes, addition of using carrier cloths with natural pigments. Dyes such as cochineal, madder, logwood, pomegranate, indigo, myrobalan, Buckthorn berry dye can be used. I bet your head is spinning, but do not worry, it will make sense once you start to observe some of the habits of this art form.

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  1. Thank you SO much for sharing this!
    That was a lot of work! SO helpful to have a visual of the different combinations.
    I have been dappling in eco printing since the beginning of the pandemic.
    I find it is good to not have expectations but to just enjoy the learning process.
    Thanks again for being so generous with your information as always.

    1. Yes! You are so right and that’s what actually makes it very addictive – like buying a lottery ticket; you might have a big win! It’s sad when only the end result is wanted and no learning of the process. Yes, it was a lot of work…

  2. Thank you, Barb, for untangling the many processes! I wish this info had been available all in one place years ago, when I began eco printing. Beginners today are so lucky! Those lovely monochromatic prints are great candidates for over-dyeing, especially with natural dyes that need no mordants, such as indigo.

  3. Thank you for all the work you have done to clarify this “mysterious” process. I have not had success with the microwave process, but will try again using this info. Funny, I just brought up my steamer pan last night to try again as well and you send along this email! 😉

  4. Love this! Thank you for great info and summaries. Do you happen to have this in a PDF or file that could be printed out and used for reference?

  5. Hi Barb

    I have a felted wool blanket and was going to try your mitt pattern. The Eco print is beautiful, so I want to try it with the blanket, and then make the mitts. The methods you describe are done with cotton. Which method works best with wool?

    1. I have printed wool many times but using the microwave needs a little more care than an immersed processing. This post may help you as well as this Some blankets are flatter and denser than others, all these factors affect the print… Do experiment first. ‘Best of luck!

  6. Thank you so much! This has given me a great insight into what you can achieve with different methods. I’d never heard of dipping the leaves into iron so I’m going to try this next time. I have tried twice to get a good green print from oak leaves and not had much luck but I’m hoping this might change my results. So kind of you to share the mystery! I will keep following what you do and I hope to learn so much more!

    Do you know what gives the leaves more tannin? Sunshine vs shade? Fallen vs picked? TIme of year etc?

    1. Actually, I was pretty clueless when I started and just kept trying… I was determined not to pay for high price class. And frankly, the variables from leaves, location, species, iron level, fabric, mordant, make for such variations in prints anyways. Even water makes a difference so I just kept seeing what worked for me. Your questions – yes, all those things make some difference. But it’s like buying lottery tickets… might be a big win! That’s what keeps us interested…

  7. I’ve been following you for some time, I really like your methods and explanations ..
    The only thing I didn’t understand is how to prepare with aluminum acetate (AA) to etch cotton fabrics ..
    In the 5 liters water then I put sodium acetate and alum, turn well then I put the already wet cotton fabric and cook for an hour?

    1. After the mordanting in AA you rinse the fabric and use right away or dry for later use. The fabric needs to be damp/wet to print. Silk and wool need less mordanting, if at all.

    1. Rest assured, my first eco printing looked like I just drove over it in the driveway… It takes a bit of trial and error and figuring out your botanicals. Myrobalan is a great addition.

  8. Thanks for putting this all in one post, Barb. In my studio, where I teach classes, I keep a series of prints hanging on the wall, like the ABCs in school classrooms, so that students can easily see the difference. It helps keep the head-spinning to a minimum.

  9. Barb hi there I love your website and follow all your methods, plus love your wackie sense of humour.
    Just wondering re alum acetate mordant for cellulose. Do you finish the process off by soaking in chalk, then rinsing, and drying. Another website says it gets rid of excess mordants in the fibre prior to eco dyeing. I loved all your tests and specific guidance to us eco dyers.
    Again, thanks for all your wonderful tips and sharing. Sally

    1. I know what you are talking about; I have tried it and it probably did help the print. Since I have a bit of an adventurous spirit when it comes to creativity I sometimes just ‘throw caution to the wind’! Did you know that you can also make calcium carbonate by grinding eggshells in a coffee bean grinder?