If you have been reading up on any of the many Facebook groups about botanical printing, you will have heard the term; dye blanket, tannin blanket or iron blanket.
These are also known as carrier cloths.
To make sure we are all on the same boat, we should get the terminology straight.
A 'blanket' is the same thing as a carrier cloth. This is usually a piece of cotton or other absorbent fabric, that is put on top of the fabric you want to print. We will call that the target piece.
What I am creating is a sandwich of the following;
Target piece (silk or wool are great)
Leaves.
Blanket.
(optionally; a barrier).
I made this visual to make it easier to follow;
Does my target piece need a mordant?
Well that depends. If you are using tannin rich leaves, you do not really have to. If you are using anything else, mordanting with aluminium tri-formate or alum will be a great idea. See also this blog for tips on your first botanical print; https://www.suzannedekel.com/post/8-keynotes-for-your-first-eco-print
If you are planning to make your blanket a dye blanket, you must use a mordant or the amazing background colour on your target piece will just wash away in an instant when you are done. By using ferrous sulfate as a mordant, the entire target piece will get a distinct darker tone, even black if you use tannin rich leaves and/or a tannin blanket (more about that later). You can see the effects of the different mordants available on your leaf prints here;
Now place your leaves on your target piece, bottom side down.
The blanket.
The best blankets are an absorbent, natural fiber, like cotton. Old molton sheets are great, French Terry cotton is too. You can recycle old sheets as a blanket for your print project and they will be amazing.
If you are not soaking your blanket in anything, there is no use for it. We soak the blanket in either a mordant, or a dye, or both.
Great dyes for blankets are; logwood that will give you a purple background, or Himalayan rhubarb for a vibrant yellow, madder roots for red and cutch for chocolaty browns. Of course your choice depends on availability and personal preference of colour. Contrary to what some people claim, you can not use indigo dyed fabrics as a blanket.
To determine the WOF you have to use the weight of the dye blanket as a reference, not the weight of the target piece.
The most common mordant for a blanket is ferrous sulfate, we call this an iron blanket.
You can re-use your blanket after use, give it a wash in the machine and start all over again.
Barriers.
There is no question that your botanical print will be very sharp and clear using a barrier. Some people use single use plastic in the shape of cling film for this, and I wish to strongly discourage such practice. There is no justification for ever using that much plastic and to throw it away after use. We can and should do better.
My fabrics are sometimes delivered in thick plastic to protect it in transit (as much as I ask my suppliers not to), and those I re-use over and over and over again as a barrier. But you could easily use another piece of cotton as a barrier, wash and re-use, or brown packaging paper which I have used many times with great result. I use that paper again as wrapping paper, it's gorgeous!
Some examples of pieces made with 'blankets';
Target Piece wool
Leaves Pecan
Blanket Cotton with ferrous sulfate (iron blanket)
Target Piece Habotai Silk
Leaves Pecan
Blanket Cotton with ferrous sulfate (iron blanket)
Target Piece Habotai Silk with alum
Leaves Pecan
Blanket Cotton with Logwood and ferrous sulfate
Target Piece Cotton jersey (with ferrous sulfate mordant)
Leaves Eucalyptus
Blanket Cotton with Tannin (myrobalan)
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