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.
Related products
Glauber’s salt
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.

Titanium oxalate
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Titanium is used both on protein and cellulose fibres, giving vibrant orange and gold tones when dyes contain tannins. As a mordant, this is relatively new and not much information abounds in books or even online. It may be the closest thing now available to replace chrome, which nobody much uses any longer.
TO USE: weigh the dry fibre or yarn. Calculate mordant required for 8 to 15% WOF (weight of fibre). Dissolve in hot water. Fill pot with sufficient water for the fibre to move, add titanium and stir. Enter fibre. Bring to 180-200 degrees F and hold 1 hour. Stir yarns frequently. Cool, remove fibre and wash well. Dye immediately or dry for later.
Some interesting results are being produced doing Eco-Printing on fabric, using Titanium as a mordant.
We cannot seem to find much information on safe disposal of a Titanium mordant bath. Nothing we've found indicates it to be particularly toxic or harmful to plumbing or sewer systems, but to be on the safe side it may be best to dispose of this outdoors on a gravel driveway or similar place.
CAUTION: wear a mask when handling powders. Wear gloves when rinsing or handling wet yarns. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.
Copper sulphate
Used as a MORDANT in natural dyeing, which allows the plant pigments to bond with the fibres.
Copper tends to take the dyed yarn colours towards the brown and green ends of the spectrum. A natural dye that comes out bright yellow with an Alum mordant will look very different with copper.
Used mainly on protein fibres such as wool, alpaca, silk. Although we love to use copper as a premordant, many dyers simply use it after dyeing to push the colours a different direction. To do this, add only 25% by weight of the usual premordanting amounts. Dissolve in hot water. Remove fibre from the dyebath, stir in the copper solution, re-enter the fibre and heat for another 15 minutes. Cool and rinse as usual.
TO USE: weigh the dry fibre. Calculate mordant required for 2% WOF (weight of fibre) and white vinegar at 40ml per 100g fibre. Weigh copper and dissolve in hot water. Fill pot with sufficient water for the fibre to move, add copper, vinegar and stir. Enter fibre. Bring to 180-200 deg F and hold 1 hour. Stir yarns frequently. Cool overnight, then wash well. Dye fibre immediately or dry for later use. These directions that include vinegar are recommended by Jenny Dean in her various natural dye books. Older recipes tend to use 8% copper sulphate all by itself, as a premordant.
Spent mordant solution is best disposed of on the ground, such as a gravel driveway. Keep well away from tree roots and anywhere that may drain to a pond or water feature, since copper sulphate is toxic to plants, fish and other aquatic life.
CAUTION: wear a mask when handling powders. Wear gloves when using copper, particularly when rinsing or handling wet yarns as can be absorbed by the skin. BEST DONE OUTDOORS or with very good ventilation. Avoid breathing fumes.
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.
