Digital Textile Printing Ink Consumption, Purge Waste & Cost

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. The 8 inputs are read from the form on every keystroke: Print Resolution, Passes, Ink Coverage, Drop Volume, Ink Density, Print Speed, Purge and Maintenance Share of Total Ink and Ink Price.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Ink on the Fabric together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Ink Cost per Square Metre, Drops per Square Millimetre, Ink Mass on the Fabric, Ink Printed, Ink Purged, Total Ink Drawn, Ink Utilisation and Ink Cost — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

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

Twelve millilitres a square metre sits squarely inside the 8 to 25 mL/m2 that production machines actually use, which is the check worth running on any ink calculation - the picolitre-to-litre conversion spans nine orders of magnitude and a single misplaced factor produces an answer that is absurd by a millionfold rather than wrong by a few per cent.

How to use it

1. Work through the input groups in order — Drop Physics and Machine & Cost. 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 Ink on the Fabric in the dark results panel — that is the headline figure, expressed in mL/m2.
4. Check the supporting rows underneath (Ink Cost per Square Metre, Drops per Square Millimetre, Ink Mass on the Fabric, Ink Printed, Ink Purged, Total Ink Drawn, Ink Utilisation and Ink Cost) 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

• Process planning — establishing Ink on the Fabric before a trial is booked, so machine time and material in Dyeing, Printing, Color Management & Chemical Control are committed against a calculated figure rather than an estimate.
• Costing and quotation — Ink on the Fabric is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Print Resolution) shows how much of the gap in Ink on the Fabric each variable explains.
• Teaching and study — the accepted ranges bracket normal Dyeing, Printing, Color Management & Chemical Control practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Drop count assumes a regular grid at the stated resolution in both axes, which greyscale heads with variable drop sizes and non-square addressing do not follow exactly - the effective drop volume is image-dependent and should be calibrated by weighing ink drawn against area printed. Coverage is summed across channels and can exceed 100%. Purge share is quoted against total ink drawn and covers spitting, capping, nozzle recovery and colour changeover, but not ink lost in a head replacement. Pretreatment chemistry, which for reactive and acid inks is a substantial separate consumable, is outside this calculation, as is the steam or dry heat needed to fix the print.
• Every input is bounded to the range normal practice occupies (Print Resolution 150 to 2400 dpi, Passes 1 to 16 and Ink Coverage 1 to 400 %, 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 12647 - process control for print production, for the tone and coverage definitions.
• ISO 105-C06 / AATCC 61 - wash fastness of the printed result, which pretreatment and ink load govern.
• ISO 13655 - spectral measurement of printed colour, for verifying coverage against a target.

Questions people ask