Basalt – 18-4214 TCX

Dye: Indigo + Iron mordant

Color: Cool grey-blue tone

Color Fastness: Excellent durability due to indigo’s inherent fastness combined with iron mordant for grey undertones

A. Cotton Dyeing Procedure (Basalt)

Step 1: Pre-mordanting with Iron

• Material: 100 g cotton
• Iron Mordant: Ferrous sulfate 4% owf (4 g)
• Water: 2 L (M:L 1:20)
• pH: Neutral (~6-7)
• Temperature: Room temperature (~25°C)
• Time: 30 minutes

Process:

1. Soak cotton in iron mordant bath for 30 minutes to allow iron to bind tannins in fibers and help develop grey tone with indigo.

Step 2: Indigo Dye Vat Preparation

• Indigo concentration: 10% owf (10 g)
• Reducing agent: Sodium hydrosulfite or natural fermentation (e.g., indigo fermentation vat)
• pH: Alkaline (pH 10-11)
• Temperature: 30-35°C

Process:

1. Prepare a reduced indigo vat (natural or chemical) ensuring the dye is soluble (leuco form) for fiber absorption.

Step 3: Indigo Dyeing

• Temperature: 30-35°C
• Time: 10 minutes per dip
• Dips: Multiple dips (4-6) with oxidation in air between dips

Process:

1. Dip iron-pretreated cotton into indigo vat for 10 minutes.
2. Remove, expose to air to oxidize leuco-indigo to insoluble blue.
3. Repeat dipping and oxidation 4-6 times until desired grey-blue depth is achieved.

Step 4: Rinse & Dry

• Rinse cotton in cold water gently to remove excess dye.
• Dry in shade.

B. Silk Dyeing Procedure (Basalt)

Step 1: Iron Mordant Pre-treatment

• Ferrous sulfate 3% owf (3 g)
• 2 L water
• Room temp, 20 min

Step 2: Indigo Vat Preparation

• Indigo 8% owf (8 g)
• Sodium hydrosulfite or natural vat, pH 10-11, 30°C

Step 3: Dyeing

• 3-4 dips, 8 minutes each, with oxidation between dips

Step 4: Rinse & Dry

• Cold water rinse, shade dry.

C. Wool Dyeing Procedure (Basalt)

Step 1: Iron Mordant Pre-treatment

• Ferrous sulfate 3% owf (3 g)
• 2 L water
• Room temp, 20-30 min

Step 2: Indigo Vat Preparation

• Indigo 8% owf (8 g)
• Sodium hydrosulfite or natural vat, pH 10-11, 30-35°C

Step 3: Dyeing

• 4-5 dips, 8-10 minutes each, with oxidation between dips

Step 4: Rinse & Dry

• Cold water rinse, shade dry.

Explanation & Reasoning:

• Iron mordant pre-treatment modifies the fiber’s chemical environment, producing a grey-blue shade rather than pure indigo blue.
• Indigo dyeing involves multiple dips to build color depth; air oxidation after each dip fixes color.
• Indigo dyeing requires alkaline pH and reducing conditions to convert indigo to soluble leuco-indigo for fiber absorption.
• Cotton tolerates higher iron and indigo concentration, wool and silk need gentler parameters to avoid fiber damage.