Back to Mordants and Additives
Calcium carbonate (Chalk)
$2.80 – $6.30
Used as a DYE ASSIST or MODIFIER in natural dyeing. Chalk can help to boost the colour uptake on certain dyes, including Madder, Munjeet and Weld, enabling more pigment to bond with the fibres by creating less acidic conditions.
TO USE: calculate amount required for .5% WOF (weight of fibre), which means half a percent. Approximately 1 teaspoon per pound of fibre. Weigh and dissolve in hot water. Add to dyebath before entering fibre. For silk, stir into dyebath after dyeing is complete and taken off the heat, then soak fibre overnight.
Dye solutions containing chalk may be safely disposed of down the drain or just poured outside in the garden.
CAUTION: wear a mask when handling powders.
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Citric acid
Used in place of vinegar, as a MORDANT on protein fibres when working with acid dyes or food colouring. Many production dyers switch to citric acid because buying jugs and jugs of vinegar gets too expensive, and vinegar makes your house smell like a pickle factory. Citric acid is odour free!
TO USE: dry crystals may be easily weighed at 5 to 8% WOF (weight of fibre). Follow dye instructions for the recommended acid amounts. Just as with vinegar, the point at which you add the acid to the dyepot can make a substantial difference in the end results. Same goes for hand painting and other methods.
TO MIX A VINEGAR SUBSTITUTE: add 200g (approximately 1 cup) of citric acid crystals to 4L of hot tap water in an empty vinegar jug. Cap and shake well until dissolved. This makes a 5% solution that can be measured and used exactly the same as for vinegar in your dye recipes.
Dye solutions containing citric acid may be safely disposed of down the drain (other than septic systems). Some dyers use baking soda to first neutralize the spent dyebath.
CAUTION: wear a mask when handling powders. Wear gloves when handling citric acid powder, as it can cause skin burns. Avoid breathing fumes (just as with vinegar): dye in a well ventilated area.
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.
Iron sulphate
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Iron darkens or "saddens" colours. It takes only a tiny amount to do this, and one must be careful with iron: too much will harshen or damage fibres. If you use iron with any regularity, consider having a dedicated pot for this purpose, as it sticks to pot surfaces and will affect the colour of future dyebaths. A chipped enamal pot is perfect.
Used mainly on protein fibres such as wool, alpaca, silk. Although it can be used as a premordant, most natural dyers use iron to alter the colour at the end of the dyeing process. If you prefer to premordant, follow the usual steps using iron at 6% WOF.
TO USE: Weigh fibre before wetting. Dye in the bath of your choice, with or without an alum premordant. Calculate iron mordant required for 2% WOF (weight of fibre). Dissolve iron in hot water. Remove fibre from warm dyepot, stir in dissolved iron and re-enter fibre. Simmer for 5 minutes, cool then wash and rinse well.
Spent mordant solution may be safely disposed of by pouring in the garden. Iron sulphate is a common soil amendment in agriculture and horticulture.
CAUTION: wear a mask when handling powders. Wear gloves when using iron, as it stains skin easily. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.
Tin Mordant
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Tin (Stannous chloride) brightens colours and really makes them "pop". However, it is one of the trickier mordants to use, and rather expensive. Some dyers prefer to premordant with tin, while many simply add "a pinch" at the end of the dye process, and heat the fibre for another fifteen minutes or so, cool and then rinse as usual. The amount recommended for this is only 25% of the usual premordanting amounts, below.
Used mainly on protein fibres such as wool, alpaca, silk. Tin can make fibre feel harsh and brittle, so do not exceed the recommended amounts. Yarns can also easily scorch during tin premordanting. Do not pack the pot too full of fibre! An upturned rack, marbles or stones can help keep yarns off the bottom of your pot.
TO USE: Weigh fibre. Calculate mordant required for .5 to 2% WOF (weight of fibre). Weigh tin and dissolve in hot water. Fill pot with sufficient water for the fibre to move, add tin and stir. Enter fibre. Bring to 180-200°F and hold 1 hour. Stir yarns frequently. Cool, remove fibre and wash well. Dye immediately or dry for later. Some dyers add cream of tartar at 5-10% WOF with tin.
Spent mordant solution may be safely disposed of by pouring in a gravel driveway or path.
CAUTION: wear a mask when handling powders. Wear gloves when using tin, as it can be absorbed by the skin. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.