Aluminum Acetate

Aluminum acetate is an alum mordant for cellulose fibers and is a recommended mordant for printing with natural dyes.  I’ve seen 5-10% weight of fiber suggested, or 7-10 grams per 100 grams of cotton fiber. Botanical colors recommends 2-4 rounded teaspoons per 100 grams of fiber.  Aluminum acetate can be made from sodium acetate and potassium aluminum sulfate and you can find instructions at Maiwa.com and various places online, but I prefer to buy it!    

Before dyeing with Aluminum Acetate, you should scour your fibers because scoured items dye more evenly, with better dye penetration, because any oils or residues that might be on the surface of the fiber are removed.  Scour with some Soda Ash and detergent or synthrapol at the very least once. 

It is often recommended that cotton and cellulose fibers should have a tannin bath before they are mordanted with aluminum acetate, but Jenny Dean has said that she does not use a tannin bath when mordanting with Aluminum Acetate.  Maiwa.com notes that some dyers omit the tannin process when using Aluminum Acetate but they have found that the tannin process results in superior lightfastness.  I have also heard of people doing a 5% WOF wheat germ soak after the Aluminum Acetate bath, instead of a tannin bath, and saying that that is a process that Michel Garcia uses as well. 

You can use a tannin extract, myrobalan, gallnuts, pomegranate skins, sumac, oak leaves or acorns, tea contains tannins, sumac leaves, cutch/acacia/wattle,or any other tannin or tannin-containing dye stuff for your tannin bath.  Certain tannin sources will impart color onto your fiber more than others like, cutch/acacia/wattle or black walnut so this is the reason why dyers may pick a certain tannin source over another.  Aleppo oak gallnuts and oak gallnut extract are a favorite because they don’t impart much of their own color to their fiber, but some people use green tea and sumac leaves are favorites as well because they won’t impart as much of their own color as some other tannin containing dye stuffs.

Put your scoured (and tannin-ed if you chose to) fibers into a hot bath of 110-120 degree water so that the fibers are covered and soak and stir for 1-2 hours or steep overnight.  I have also read that you can just use hot tap water and just let it steep for at least 2 hours or over night, and it is said that no additional heat is needed.  Aluminum Acetate will form particles if it is heated above 140 degrees.

The step of chalking, whether to or not, draws varied opinions. Some dyers never chalk. Jenny Dean has mentioned that she does not chalk.  Chalking, sometimes called dunging because cow dung high in phosphates was used, is a step that is especially done if someone mordants cotton with aluminum acetate without first doing a tannin bath.  Then the mordant needs fixed to the fibers before dyeing with chalk. So, the chalk acts to bond/fix the mordant to the fibers.   I have read it explained that chalk would raise the pH so that the fibers are not as acidic from the aluminum acetate.  If you have done a tannin bath before mordanting with aluminum acetate, then you don’t need to fix the fibers with chalk, some say.  There is an article on Catharine Ellis’s blog site, blog.ellistextiles.com, named The Effect of pH on Yellow Dyes from the Garden, showing the much brightened results of dye baths with chalk added to them. 

So, whether to chalk, or not, is up to you, if you have used a tannin bath before using aluminum acetate.  If you choose to chalk, you can add 50 grams of chalk (calcium carbonate) to 5 quarts of warm water and fully wet the fiber.  I read opinions that said that the fiber should be dry prior to being wetted in the chalk solution.  Rinse the fiber well after the chalking.  This chalking solution can be kept and refreshed after every 22lbs of fiber.  In the article on Catharine Ellis’s blog that I mentioned, she used 1 Tbs of chalk in her 4 liter dye baths, so the chalk was in the dye bath along with the dye, and her pictures show a much brightened effect.

You can use wheat bran as an alternative to chalk.  Use 3.5oz of wheat bran to 5 quarts of warm water.  Soak the wheat bran for about 30 minutes before you add the fiber, so that it is wetted. 

You can move immediately to dyeing after scouring, tannin-ing and chalking, or you can dry the fiber completely and store to dye at a later time.  Just make sure to thoroughly wet-out your fibers before dyeing, if you have dried and stored them, so that the uptake of dye will be even. 

This sheet is just to give you very basic instructions on how to mordant with aluminum acetate.   Maiwa.com offers excellent online information on everything you need to know.  Specifically, the naturaldyes.ca/how-to-mordant-cellulose  page will walk you through the process. 

Wildcolours.co.uk/html/aluminium_acetate.html page also has great information on dyeing with aluminum acetate as well, and mentions the newer mordant Aluminum lactate, which is also used in exactly the same way as aluminum acetate.