With the last editions to the supply store of aluminium lactate and ferrous lactate, more side-by-side testing was in order.
What really is the best alum mordant for cellulose? Does it make much of a difference?
Why would we use anything but regular alum?
Regular alum (Al) should always be used on cellulose like cotton and linen as a two-step method: first, you do a tanning with a clear tannin such as oak gall or tara, and then you do a mordant with alum at around 15%. Some repeat those two steps again. So tanning, alum, tanning, alum.
That's a lot of work and time to invest, and a lot of water for those extra rinse processes.
The alum family of triformate, acetate, and lactate are one-step mordants, you 'could' do that extra step of tanning, but you do not have to. That is a huge time and water saver!
Another added bonus is you need less of these mordants. Between 5-10% WOF can be more than enough for a solid mordanting, so even though the new mordants are more expensive, in the end, it pans out more or less the same in cost.
In this blog I will compare between aluminium lactate, aluminium acetate, aluminium triformate, and regular alum, on different fabrics, to show you the difference in colors. After all, if the results are not impressive, it is not worth it at all.
What is aluminium lactate?
Aluminium lactate (Al-lact) is the new mordant on the block that is made with lactic acid, which is made by fermentation of renewable starches in the food industry such as beet sugar, cane sugar, corn, and tapioca. Aluminium lactate is used in food and cosmetics ( E328). It is an active ingredient in toothpaste and moisturizers, it has astringent and anti-inflammatory, and anti-bacterial properties. It looks like it has been used for cellulose for a while now in the larger textile and leather industries, but only recently made its' way to the hobby dyers.
Aluminium acetate (AA) is based on alum combined with acetic acid, homemade or store-bought. There are different types of aluminium acetate in order of strength:
Aluminium monoacetate
Basic Aluminium Acetate (Aluminium diacetate)
Aluminium triacetate
For this experiment, I used an aluminium acetate I have bought somewhere years ago. Checking back, it does not say which type of acetate it is...
Aluminium triformate (ATF) is the aluminium salt of formic acid, chemical formula Al(HCOO)3. Formic acid (HCO2H) is the simplest of carboxylic acids, it is regularly used in processing textiles and leather. In nature, it is found in the stings and bites of many insects of the order Hymenoptera, including bees and ants, this is why it can give a tingling sensation on your skin and you should use gloves when working with it (as we all should, for all mordants).
Aluminium triformate is used a lot with wool and with cellulose and can be used as a cold batch mordant, meaning you just make a mordant bath that you reuse many times until it gets depleted. (I have yet to see how aluminium lactate holds up over time, and if you can use it the same way).
Regular alum was also used on one set of fabrics, to show the clear difference. The reason regular alum is not mordanting cellulose too well on its' own is that it is missing a 'bite' factor like an acid or an alkaline.
Test I - 10% Aluminium lactate on different fabrics
For the samples, I took the same-sized pieces of fabric, four sets in total. The fabrics were:
Vintage dutch linen
Beaver cotton
Vegan wool (made from plants, a sample I ordered to test before I decide if I want to run it in the store)
Silk noil (to see if the same holds for protein fibers)
Each set was 32 grams. The sets were all scoured for one hour in soapy water, and then rinsed.
Each set was mordanted at 10% WOF (3.2 grams) of mordant. The mordant was prepared at 30ºC, in two liters of water, and sets were entered and turned around regularly. Time in mordant was around two hours. I definitely did not work the fabric enough (doing a million other things at the same time) and it shows in blotchy results.
Set one alum
Set two aluminium acetate
Set three aluminium triformate
Set four aluminium lactate
Dissolving the mordants:
Alum is dissolvable in really hot water
Aluminium acetate and triformate dissolve easily in warm water.
Aluminium lactate does not dissolve so easily in cold water and you should whisk it in cold water separately before adding it to the main bath or use hot water to dissolve more easily.
The sets were all rinsed in clean water twice and then dyed in a dye bath with 5% WOF cochineal extract. The dye bath was heated to 80ºC and the fabrics were dyed for 1.5 hour while stirring regularly.
The results for each set from left to right:
Set one alum
Set two aluminium acetate
Set three aluminium triformate
Set four aluminium lactate
In conclusion: Aluminium lactate is a wonderful alum-based mordant for all fibers. The colors are full and vibrant. It is environmentally friendly and made with renewable materials that are readily available in the food industry. Budget-wise, I would claim that it can pan out cheaper than using double mordants or even homemade alum and soda mordant for example, simply because you can use it with such low percentages.
I like this mordant a lot and I will continue to work with it for more different colors for you and update in the blog when I have the results. I have high hopes for botanical printing as well.