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Oxalic acid
$6.00 – $10.80
Used occasionally as an ASSIST in natural dyeing. Oxalic acid will alter the shades of cochineal dyebaths, pushing them towards brilliant orange-red.
Also used to help absorption of Tin when premordanting. Dissolve with the tin in hot water at 2% WOF then add to premordanting water, mix and enter fibre.
TO USE: with cochineal baths, use at 2% WOF (weight of fibre). Dissolve first in hot water then mix into dyebath before entering fibre.
Dispose of spent dyebath on the ground.
CAUTION: POISON!!! Wear a mask when handling powders, absolutely wear gloves at every stage with Oxalic acid. MUST BE DONE OUTDOORS: fumes can be an extreme irritant.
Related products
Alum (Aluminum sulphate)
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
This is Potassium aluminum sulphate, the preferred form of alum for use as a mordant. This IS NOT pickling alum and should not be consumed.
Used mainly on protein fibres such as wool, alpaca, silk. Usually used in combination with cream of tartar. Many natural dyers do a premordanting of the fibre with alum, while others add it directly to the dyebath (particularly with loose fibre such as fleece). Also sometimes used in combination with tannic acid to premordant cellulose fibres such as cotton.
TO USE: calculate mordant required for 8 to 15% WOF (weight of fibre) and 4 to 6% WOF cream of tartar. Weigh and dissolve in hot water. Fill pot with sufficient water for the fibre to move, add alum and cream of tartar and stir. Enter fibre. Bring to 180-200°F and hold 1 hour. Stir yarns frequently but fleece only occasionally. Cool overnight, then wash in soapy water and rinse thoroughly. Dye immediately or dry the yarns to dye later.
Spent mordant solution may be safely disposed of down the drain (except for septic systems). It also may be poured around garden plants that prefer acidic soil conditions.
CAUTION: wear a mask when handling powders. Wear gloves when using alum, particularly when rinsing or handling wet yarns as it is very drying to the skin. Best done outdoors or with very good ventilation.
Thiourea Dioxide
Sometimes called Thiox. Used in the INDIGO VAT dye process, thiox removes oxygen from the vat solution, allowing the indigo to work its magic. Thiox is also a colour remover, and is used for that purpose in discharge dyeing, to create white patterns on a coloured background.
TO USE: Follow the specific indigo vat recipe, for amounts and timing.
Dispose of spent dyebath in the usual way, most likely down the drain.
Thiourea dioxide has a shelf life but it's longer than some things you read might indicate. If the powder has a distinctive yellow look, it has probably oxidized to some degree and may no longer be effective. Store in a cool, dry place out of the light i.e. in a cupboard in the house, not out in the garage.
CAUTION: Should be done OUTDOORS ONLY or with excellent ventilation. Avoid breathing fumes. Wear a mask when handling powders. Wear gloves.
Myrobalan, Ground
Ground nuts of a tropical tree, Terminalia chebula.
Use on protein or cellulose fibres. Considered both a mordant and a dye, because of the high tannin content. Yields a light butter-yellow to beige or mushroom. Substantive, no mordant needed. Use at 15-20% WOF as a mordant on cellulose fibres. As a dye, use at 20-30% WOF for medium shades.
TO USE:soak 24 hrs in water to dissolve. Add more water if necessary and enter fibre. Bring to a high simmer for 1 hour. Let fibre cool overnight.
Light and washfastness: good.
Pomegranate, Ground Rind
Powdered/ground rind from the rinds of pomegranate fruits, Punica granatum. NOTE: this is NOT EXTRACT. This is the kind to use if you want to try it as a natural mordant.
We list this as a natural dye, but it is sometimes used as a mordant.
Use on protein or cellulose fibres. Yields soft yellows to green-yellows or gold. Substantive but pre-mordanting recommended. Use at 15-20% WOF for medium shades.
TO USE: soak 24 hours in hot water, stirring occasionally, then strain. Place liquid and fibre in dyepot and add more water if necessary. Bring to a high simmer for 1 hour. Let fibre cool in dye liquor for at least one more hour or overnight then wash and rinse.
Light and washfastness: moderate to good.