Back to Mordants and Additives
Glauber’s salt
$4.00 – $7.20
Sodium sulphate. Used as a LEVELLER in both synthetic and natural dyeing.
Glauber’s salt slows down the colour uptake of the dye, encouraging more even and level strike. This is particularly useful when dyeing soft pastel shades.
TO USE: Calculate amount required for 10 to 50% WOF (weight of fibre), lower amounts for softer shades, higher amounts for deeper colours. Dissolve in hot water and add in stages during dyeing, as the bath temperature rises but before dye strikes.
Dispose of spent dyebath in your usual way. Down the drain is fine.
CAUTION: wear a mask when handling powders.
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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.
Soda ash
Used with fibre reactive dyes as a colour FIXATIVE. Soda ash raises the pH and allows the dye to bond with the fibre. Generally used only with cellulose (plant) fibres such as cotton or flax. Also known as washing soda or sal soda, though this is a more pure form that the washing soda sold in supermarkets.
Also sometimes used in natural dyeing to create more alkaline conditions, and thus altering the colour with certain plants. Extensively used for indigo vat dyeing.
TO USE: Follow dye manufacturer’s directions for amounts and timing.
Dispose of spent dyebath in the usual way, most likely down the drain.
CAUTION: Wear a mask when handling powders. Wear gloves, can be a skin irritant.
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.
Tannin Blend
This is a blend of NATURALLY-SOURCED Tannin, usually from Quebracho and Sumac, possibly others. It will leave your plant fibres or fabrics a soft red-brown base colour before using other dyes.
Used mainly on as a MORDANT on cellulose fibres such as cotton, usually in combination with Alum.
TO USE: weigh dry fibre. Calculate mordant required at 15 to 20%% WOF (weight of fibre) each of Tannic Acid and Alum. Weigh mordants and dissolve in hot water in separate plastic or non-reactive containers. Add wetted fibre to Alum solution and soak for 12 to 24 hours. Rinse and place in Tannic Acid solution for 12 to 24 hours. Rinse again and place back in Alum solution for 12 to 24 hours. Wash and rinse well, then dye or dry for later use.
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 tannins, particularly when rinsing or handling wet yarns as they can cause skin irritation and staining.