White ink trials:
coverage, wash & jetting.

DTF and DTG white ink should be evaluated for both coverage and repeatable printing. Follow the ink grade and printer instructions for agitation, circulation, nozzle checks and idle periods. An opaque sample is useful, but it does not show how the white channel will behave through a production shift.

1. Compare white coverage after the complete process

For a practical garment comparison, use the same batch of dark fabric and the same test artwork: a solid white patch, fine white detail and a CMYK image over the white foundation. Compare fully cured samples under consistent lighting, keeping an approved sample alongside each trial. Look for substrate show-through, pinholes, uneven coverage and changes in overprinted colour.

• DTF: hold film, powder, white-layer settings, powder curing, heat-press conditions and peel procedure constant.
• DTG: hold fabric, pretreatment application and drying, white-layer settings and final curing constant.
• Instrument readings: record instrument, measurement mode, aperture, backing and measurement locations. Report measured lightness as lightness, not as an invented opacity percentage.

For a formal measurement, ISO 23498:2022 covers visual opacity of printed white ink. Its public introduction stresses that the result belongs to the printed ink and its printing configuration. Substrate restrictions apply: do not label a visual comparison on black garments as an ISO 23498 test. Ask the laboratory to confirm a suitable specimen and method.

Record: ink grade and batch; fabric and colour; film / powder or pretreatment; RIP profile, passes and white laydown setting; curing / pressing conditions; lighting and measurement setup; reference sample; observed defects.

2. Agree the wash conditions before comparing ratings

Test the completed, cured print on the intended fabric—not liquid ink alone. Retain an unwashed control. A laboratory can select an appropriate procedure from ISO 105-C06:2010, which addresses textile colour fastness to domestic and commercial laundering. The exact procedure matters; a grade without the method and conditions is not a complete comparison.

• Sample preparation: identify fabric, printing route, ink batch, curing conditions and the conditioning interval before washing.
• Wash setup: agree the standard edition and procedure, temperature, time, detergent and concentration, bleach if applicable, mechanical action / load, cycle count and drying method.
• Evaluation: record colour change and staining using the selected method. Separately photograph cracking, peeling, edge lift and loss of adhesion under consistent lighting.
• Wear simulation: a buyer-agreed home-wash trial should follow the garment care limits and document the actual programme. Do not present it as a standardized laboratory test or convert cycles into a guaranteed garment lifespan.

Dry and wet rubbing are different checks. ISO 105-X12:2016 addresses colour fastness to rubbing; a rubbing result does not replace a wash result. There is no single washing temperature or “number of washes” prescribed here for every ink, fabric and process.

Record: method / procedure; wash temperature and duration; detergent; load; cycles; drying; before-and-after photographs; colour change / staining results; visible print damage. Mark results as pending until the trial or laboratory report is available.

3. Check nozzles, then test the real production pattern

Confirm the printer model, exact printhead variant and aqueous-ink suitability with the equipment supplier before loading a new ink. A shared head-family name is not proof of compatibility. Use the approved changeover, agitation and circulation procedure; do not mix inks or change drive voltage / waveform on the basis of this guide.

Epson's SC-F1070 nozzle-check instructions recommend checking before printing and specify transparent media or coloured paper for the white-ink check on that model. Use the check media and maintenance procedure prescribed for your own printer. This equipment example is not an Epson approval of M-inkjet ink.

1. Baseline: save a dated nozzle pattern after approved preparation; record missing or deflected nozzles and existing machine condition.
2. Print run: agree run duration, artwork coverage, RIP settings, passes and production speed. Log room temperature / humidity, white circulation and any maintenance or interruptions.
3. End of run: repeat the nozzle pattern and comparison artwork. Record dropouts, banding or coverage changes rather than only keeping the best print.
4. Idle / restart: use an agreed idle interval representative of actual work, within the printer's permitted routine. Save the restart pattern and record cleaning actions and recovery. Stop and investigate recurring loss of output.

Record: printer / head variant; ink batch; environment; RIP / pass settings; start and finish times; print coverage; idle interval; before / after / restart nozzle patterns; cleaning events. Confirm the acceptance criteria with the buyer before running the test.

Why can white pigment ink settle?

White pigment is dispersed in a liquid vehicle and can settle during storage or inactivity. The useful question is how the supplied grade should be maintained and whether it returns to a uniform working condition using its approved procedure. A claim of “no sediment” is not a substitute for practical handling guidance.

Ask for the recommended storage conditions, shelf life and in-machine routine. Do not assume that two white inks use the same agitation schedule or that a routine for one printer applies to another.

Build the routine around the actual machine

Before production

Check the ink identity and condition, complete the prescribed agitation or circulation procedure, and inspect a nozzle-check pattern. Attend to the capping and wiping components as required by the printer manual. Save a reference pattern when the machine is working correctly.

During production and idle periods

Follow scheduled maintenance and respond to recurring missing channels before changing colour or white-density settings. Confirm the manufacturer's procedure for extended inactivity before a shutdown. Avoid adding water, solvents or another ink to correct a problem without explicit instructions for that formulation.

What if the printed white looks uneven?

Start by separating a jetting problem from a process problem. Inspect nozzle output, white-layer settings and the substrate preparation. On DTG garments, pretreatment uniformity and drying can affect the white foundation. On DTF film, review the film and selected printing conditions before judging the finished transfer.

Epson's white-ink troubleshooting guidance checks nozzle condition, ink agitation and pretreatment among several causes of poor white output. Its specific schedule applies to the listed equipment; use your own printer's instructions for operating intervals.

Qualify more than opacity

Run the intended artwork and fabric through the complete process. Compare coverage, fine detail, colour overprint, surface feel and cured performance. Include a restart after an agreed idle period if that reflects normal production. Record the maintenance actions needed to recover the accepted output.

Match the white pigment ink grade to either the DTF ink system or DTG ink system. Share the printer model, ink-delivery arrangement and typical idle time when requesting samples.