Dyeing Recipe & Bulk Dosing Calculator

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. Bath volume is settled first, because it is the denominator for every auxiliary in the recipe. Liquor ratio is a machine property rather than a recipe choice: a winch runs long, a jigger and a modern airflow jet run short, and a part load raises the running ratio above the rated figure.
2. Dye is calculated on the goods. Shade depth is quoted on weight of fabric, so 2.5% of a 500 kg batch is 12.5 kg of dye whether the machine holds 2,500 litres or 7,500. That is exactly what makes a lab dip transferable to bulk — depth of shade is set by dye per unit of fibre, not by dye per litre.
3. The strength correction converts the recipe figure into what the store actually issues. Lab recipes are written against a 100% standard-strength product; the drum on the floor may be 150% or 200%, and the correction is applied to the weight, never to the shade percentage.
4. Salt and alkali are multiplied by the litres, then divided by 1000 to reach kilograms. This is the step where recipes go wrong, and the size of the error is worth knowing. Reading a bath concentration as a dose per kilogram of goods — 60 g/L taken as 60 g per kg of fabric — gives 30 kg instead of 240 kg on this batch, short by exactly the liquor ratio. Reading the same 60 g/L as 60% owf gives 300 kg, over by 10 / liquorRatio. Either way the machine, not the recipe, sets the size of the mistake.
5. Bath dye concentration is calculated back as a cross-check on dissolution and dosing. It tells you how much colour the dissolving vessel has to carry into the machine, and whether the stock solution volume fits the dosing tank and the dosing profile.
6. Finally the auxiliary kilograms are read against dissolving and metering capacity. Salt at a few hundred kilograms per batch has to be dissolved or brine-dosed and metered in over a profile, not tipped in; the calculated figure is a purchase and dosing quantity, not a shortcut past the addition sequence.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

Substituting

A 500 kg dark shade on a 1:8 machine. The salt at 240.00 kg outweighs the dye at 12.50 kg by about nineteen to one, so the tonnage handled in the dye kitchen and the dissolved-solids load leaving in the effluent sit in the auxiliary — even though the dye is by far the more expensive material per kilogram and still dominates the recipe cost. Running the same batch at 1:5 leaves the dye untouched at 12.50 kg but drops the salt to 150.00 kg and the alkali to 50.00 kg; that is where a short-liquor machine pays for itself. The strength field at 100% makes its correction invisible here — on a 200% brand the same recipe weighs out 6.25 kg and the bath concentration falls to 1.56 g/L.

How to use it

1. Work through the input groups in order — Batch and Recipe. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Dye Required in the dark results panel — that is the headline figure, expressed in kg.
4. Check the supporting rows underneath (Bath Volume, Salt Required, Alkali Required and Dye Concentration in Bath) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Lab dip to bulk scaling — an approved beaker recipe at 1:20 carries its dye percentage straight across to a 1:8 jet, while every g/L auxiliary has to be requoted in kilograms against the new bath volume.
• Dye kitchen weighing sheets — turning the recipe into the kilograms issued per batch, and checking that the dissolved stock solution fits the dissolving vessel and dosing tank before the machine is loaded.
• Costing — dye at % owf is normally the dominant chemical cost in medium and dark shades, while salt is the largest single tonnage the dyehouse buys and handles.
• Effluent and salt load planning — total salt per batch is what reaches the effluent as dissolved solids and chloride, so the kilogram figure is the number that goes into discharge consent and ZLD evaporator load calculations.
• Dye brand substitution — checking what a change from a 100% to a 150% or 200% strength product does to the weighed quantity when the approved shade percentage stays fixed.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Commercial dyes are sold at varying strengths against a standard. A 200% brand needs half the weight, so always confirm the strength before scaling a lab dip.
• Every input is bounded to the range normal practice occupies (Fabric Batch Weight 1 to 100000 kg, Liquor Ratio (1 : x) 1 to 50 :1 and Shade Depth 0.001 to 20 % owf, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Standards and further reading

• ISO 105-J03 — calculation of colour differences. This is the arithmetic behind the pass or fail when the bulk lot is compared against the approved lab dip after the recipe is scaled.
• ISO 105-C06 — colour fastness to domestic and commercial laundering, the check on whether the unfixed dye implied by a deep recipe was actually washed off.
• ISO 105-X12 and AATCC 8 — colour fastness to rubbing and crocking. Over-dosed or under-washed dark shades fail here before they fail anywhere else.
• ASTM D2495 — moisture in cotton by oven drying, which establishes the weight basis the shade percentage is quoted against when a batch weight is disputed.
• Relative dye strength has no single test designation that transfers between suppliers. Mill practice is to check the drum against a retained reference by lab dip, or by spectrophotometric comparison of solutions made up at equal concentration, and to record the strength used on the batch card.

Questions people ask