A woman, Sahara Johnson from the Brooklyn Textile Arts Center, washes cloth in a clear bowl. She stirs an orange dye that is simmering in a pot.
NARRATOR:
The natural dyeing of textiles is an extremely easy and accessible way to transform that boring white tee into a landscape of a vibrant natural hues. It's really quite easy to do at home, and there are tons of household items you can use in the process. We recently visited the Brooklyn Textile Arts Center to get a demo on how to do it, and we'll also explain some of the basic chemistry that's going on with the process along the way.
Text on screen — 'The Chemistry Of Natural Dyes. Produced by the American Chemical Society.' Sahara addresses the camera. In front of her are two large pots on a stove, various jars containing colourful substances, and a cut orange.
SAHARA JOHNSON:
I'm Sahara Johnson. I am an intern at Textile Arts Center in Brooklyn. And right now we're doing a demonstration on natural dyeing. The process of this is taking natural things from the earth, like fruits and vegetables, different roots, et cetera, et cetera, and taking the colour from them and translating them into a fibre.
Sahara takes a glass bowl from behind her that contains silk in water.
SAHARA JOHNSON:
So, right here I have silk that is being wetted. When you are doing natural dyeing, you never want to directly put in a dry fibre into the dye bath — it doesn't translate the colour as well. So right here I'm wetting it.
Sahara picks up one of the jars that contains cut-up purple matter.
SAHARA JOHNSON:
So right here is red cabbage. It's one of my favourite things to dye with. It's really pH-sensitive so it changes colour really readily.
Sahara picks up another jar that contains small greyish balls.
SAHARA JOHNSON:
And right here is cochineal, which is actually not a plant — it's a little bug found on cacti.
Close-up shot of a cactus branch with a number of little ball-like grey-blue creatures upon it.
SAHARA JOHNSON:
Yeah. And it's one of the most ancient forms of red. It's really, really vibrant. You'll see in a bit, so…
NARRATOR:
With these two natural dyes — red cabbage and cochineal — there's one very big difference in how they work. Cabbage is what is called a substantive dye. It contains a pigment called an 'anthocyanin' which is water-soluble. This means that the pigment molecule can directly bond to a natural fibre on its own. Cochineal, on the other hand, is known as an adjective dye. Adjective dyes require something to stop the dye from washing out of a fibre. Cochineal's an anthraquinone dye which is a red dye that requires a bonding material called a 'mordant'. The mordanting process is when fibres are treated with a metal salt solution such as aluminum, chromium, copper, iron or tin salts, creating a lasting bond between the dye and the fibre.
Text on screen — 'Mordanting.' The chemical symbols for aluminum, 'Al', chromium, 'Cr', copper, 'Cu', iron, 'Fe', and tin salt, 'Sn', appear.
NARRATOR:
The mordant basically allows the dye molecules to lock tightly with the fibres. Sahara, in this case, is using a substance called 'alum' for her mordant in a cochineal dye. This is a substance that's more commonly used in the kitchen for pickling.
Sahara places red cabbage from the jar into one of the pots on the stove.
SAHARA JOHNSON:
Say I wanted to get a lavender colour rather than, like, a deep, like, royal purple. I wouldn't necessarily leave this in for very long. Um… just put the whole thing in. And then I'll do the cochineal in this one.
Sahara pours cochineal from the jar into the second pot.
NARRATOR:
As we just learned, red cabbage is anthocyanin dye. What's interesting about the colour of anthocyanin pigment is that its pH directly affects the range of its colour. By introducing an acid to this pigment, anthocyanins will turn red. By introducing a base, it will turn more of blue-ish green colour. At home, you can add lemon juice to the dye as an acid, or for a base, you can use baking soda. Keep this in mind while dyeing with red cabbage. You actually have a lot of colourful options.
SAHARA JOHNSON:
Right now I am taking out my dye matter. I'm pretty satisfied with the colour that has been extracted, so just taking this out to stop that process from happening. So, now I've strained out the cabbage from the dye bath, there'll be no more extraction happening and now I'm going to add my fibre.
Sahara takes the silk out of the water in the glass bowl. She lowers it into the pot that had contained the red cabbage. It immediately begins soaking purple into the silk. She puts a second piece of silk into the pot containing cochineal that starts staining red. Text on screen — 'Moments later.'
SAHARA JOHNSON:
I think we're about good with this. I'm pretty content with this pink and this lavender. So I'm gonna take it out of the dye bath and I'm going to rinse it with water and pH-neutral soap.
NARRATOR:
It's very important to remember that when rinsing your fibre of excess dye, you have to use pH-neutral soap. Such soaps are very common and can be found at virtually every grocery store. Pro tip — most pH-neutral soaps are completely clear. If your soap is not neutral, you will, in fact, alter the colour of your fibre.
After washing in neutral soap, Sahara squeezes water out of the silk. It is now a light lavender colour.
SAHARA JOHNSON:
There is my lovely lavender silk. Yeah. (Giggles) Fun stuff. (Giggles) And then we'll take out the cochineal.
Sahara removes the silk from the pot containing cochineal. It is bright red in spots and faded red in others.
SAHARA JOHNSON:
And yeah. It's very spotted but I like it. I think it's really beautiful.
NARRATOR:
Now that you know the basics of natural dyes, you can try it out at home with tons of different natural products. One last thing to remember about these dyes is that they do change colour over time and can slowly fade or go through slight variations in colour. If you aren't happy with the colour, you can always just go back in and dye it again. Also, you can try mixing dyes to produce a huge range of different colours.
SAHARA JOHNSON:
So, this is a really, really easy process to do, and that I encourage you all to try at home. A lot of household items, like the turmeric and the red cabbage, can be found at your local grocery store, anywhere, so, yeah, everything is really accessible and definitely get to it.
Text on screen — 'ACS, Chemistry for Life. American Chemical Society. freemake.com'.