Because denim processing involves multiple distinct stages—ranging from continuous yarn dyeing to garment finishing in a laundry—there is no single “universal” dosage. Dosage rates depend entirely on the equipment layout (liquor ratio), the concentration of the commercial auxiliary, and the desired depth of shade or wash effect.
Below is a technical breakdown of standard industrial dosage ranges based on typical commercial chemical concentrations (100％ active or standard commercial dilutions).
1. Continuous Warp Dyeing Auxiliaries (Slasher / Rope Dyeing)
In continuous ranges, chemicals are continuously replenished in the pad troughs based on the wet pick-up rate of the yarn (usually 60% –70%). Dosages here are calculated per liter of dye liquor (g/L).
| Auxiliary Function | Standard Dosage Range | Operational Notes |
| Penetrant / Wetting Agent | 1.0 – 3.0 g/L | Must be low-foaming and highly stable to caustic soda (NaOH). |
| Chelating / Dispersing Agent | 0.5 – 2.0 g/L | Prevents iron or hardness interference; protects indigo stability. |
| Sodium Hydroxide (Caustic, 100%) | 2.0 – 5.0 g/L | Adjusted dynamically to maintain a strict pH of 11.5 – 12.2. |
| Sodium Hydrosulfite (Reducer) | 1.5 – 4.0 g/L | Monitored via redox potential (typically -650 to -750 mV. |
| Indigo Leveling Agent | 1.0 – 3.0 g/L | Controls diffusion rate to preserve the ring-dyed white core. |
2. Garment Washing & Finishing Auxiliaries (Laundry Stage)
In garment laundries, processing happens in batches inside industrial belly washers or front-loading machines. Dosages are typically calculated based on the Weight of Goods (o.w.g.) or Weight of Fabric (o.w.f.), assuming a standard liquor ratio between $1:5$ and 1:10.
Desizing & Bio-Abrasion
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Alpha-Amylase (Desizing Enzyme): 0.5 – 2.0 o.w.g.
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Application: Run at 50℃–60℃ for 10–15 minutes alongside a non-ionic wetting agent（0.5–1.0 g/L) to completely strip out sizing starch.
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Cellulase Enzymes (Stone-wash effect):
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Acid Cellulase: 0.3% – 1.0% o.w.g. (High activity, shorter cycle times of 30min – 45 min, but higher risk of backstaining and fabric strength loss).
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Neutral Cellulase: 0.8% – 2.5% o.w.g. (Operates at pH 6.0–7.5; gives high contrast, very clean highlights, and minimal backstaining).
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Contrast Management & Protection
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Anti-Backstaining Agents (Polymeric Suspensions): 1.0 – 3.0 g/L (or 0.5% – 1.5% o.w.g.)
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Application: Added directly to the enzyme bath or the subsequent rinse bath. Essential for keeping pocket linings and white fill-yarns bright during color stripping.
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Anti-Creasing / Lubricating Agents: 1.0 – 2.0 g/L
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Application: Added to the very first bath before the denim gets wet to prevent permanent mechanical crease marks (“streak marks”) during high-speed rotation.
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3. Denim Printing Auxiliaries
Printing applications require high viscosity to hold fine patterns. Dosages here are calculated based on the total weight of the printing paste formulations (grams per kilogram, g/kg).
Discharge Printing Paste (Indigo Destruction)
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Synthetic Polyacrylate Thickener: 25 – 45 g/kg (Adjusted until the paste reaches the required rheology/viscosity for rotary or flat-bed screens).
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Sodium Formaldehyde Sulfoxylate (Rongalite / Reducer): 80 – 150 g/kg (High concentrations are required to completely break down surface-bound indigo during downstream steaming).
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Penetrating Auxiliaries (Acid-stable): 5 – 15 g/kg.
Laser Engraving Enhancers (Pre-Spray)
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Laser Booster Auxiliaries: 20 – 50 g/L
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Application: Applied via localized low-wet-pickup spray systems or exhaust padding before drying and laser burning. Enhances the contrast of the laser pattern by 15–20% without burning through the cotton matrix.
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Critical Adjustments: Always factor in commercial concentration variations. If you transition from a standard liquid enzyme to a highly concentrated powder, your dosage might drop from 2.0% down to 0.2% o.w.g. Similarly, water hardness above 150 ppm will require you to scale up your chelator dosage by 20％ – 30% to maintain the same leveling efficiency.