Pigment Digital Printing Pretreatment Solids vs. Fabric Hand: How to Balance Color Yield and Softness

Balance pigment digital printing pretreatment by the dry deposit on the fabric, not bath solids or viscosity alone. More deposit may improve color and definition while restricting fabric movement. Select the lowest repeatable add-on range that meets the approved shade, fabric-hand and durability requirements for the actual ink, substrate and curing process.

A pigment print can look stronger after increasing pretreatment concentration yet feel noticeably less supple. Reducing the treatment may restore softness but introduce bleeding, weak white coverage or inconsistent color. The useful question is not simply how much pretreatment to add. It is which material remains on the fabric, where it is deposited and whether the complete printed system meets its end-use requirements.

A darker unwashed print or a softer freshly dried sample is insufficient evidence by itself. Compare treated blanks and printed fabric after the same conditioning, curing and agreed laundering sequence; retain separate acceptance gates for hand, dry rubbing, wet rubbing and wash durability.

This guide covers direct pigment inkjet printing onto textiles, including roll-to-roll and direct-to-garment applications where relevant. It does not describe direct-to-film transfer printing, conventional screen-printing paste formulation or disperse-dye thermofixation. Platform-specific pretreatment, ink and curing instructions remain the starting point for production trials.

1. Pretreatment Solids, Binder Solids and Dry Add-On Are Different Quantities

“Solids” can refer to a commercial concentrate, a diluted working bath or the material deposited on fabric. Record which basis is being discussed before comparing products. Otherwise, a lower quoted dosage may be mistaken for a lower fabric loading, or a high solids result may be misread as a high binder content.

Term	Meaning	What it does not establish
Commercial product dosage	Mass or volume of supplied product added to a defined bath quantity.	The amount of binder or total dry deposit without composition data.
Product nonvolatile content	Residue remaining under a specified solids-test procedure.	A universal measure of active polymer or effective ink immobilization.
Working-bath total solids	Nonvolatile contribution of all bath ingredients on a stated basis.	How much the application process deposits on fabric.
Binder solids	The film-forming binder fraction, when separately known.	Total solids from salts, thickeners, fixatives and other additives.
Pretreatment dry add-on	Deposited pretreatment solids per dry fabric mass or treated area.	The subsequent ink and finishing deposits.
Complete printed-system deposit	Retained contributions from pretreatment, ink and any additional finish.	Hand or durability without information about chemistry and distribution.

A pigment pretreatment may use ionic components to immobilize an incoming ink, polymers to control spreading, a binder contribution, or combinations of these functions. It should not automatically be described as a binder bath. Conversely, pigment ink may already contain a binder, while another platform may distribute binding functions across several process stages.

Manufacturer documentation distinguishes ink binders from complementary pretreatment formulations, illustrating why these roles should be tracked separately. [1] Confirm the architecture of the actual system before changing one component. A supplier can often provide useful dosage and compatibility guidance without disclosing its proprietary formulation.

Measure nonvolatile content using an agreed procedure with stated drying conditions and sample handling. Some materials retain moisture or lose volatile components differently during testing. Conductivity and refractometer readings may support a calibrated process-control method, but neither independently identifies binder content or gives a universal total-solids conversion across unrelated products.

2. Why Stronger Color Does Not Automatically Mean a Better Pigment Print

Pretreatment can limit lateral spreading and excessive penetration, keeping more colorant in an optically useful part of the fabric surface. The result may be stronger apparent color, cleaner boundaries or better white-ink coverage at the same ink setting. This is an ink-placement effect, not proof that the pigment has become more securely attached.

In an industrial-scale pigment inkjet study on cotton and polyester, pretreatment improved color intensity and gamut, while rubbing results remained poor for the tested systems. The researchers associated that problem with increased surface pigment. [2] The study supports evaluating color and crockfastness separately; it does not mean every surface-retaining pretreatment reduces durability.

Use three acceptance targets

• Color and image: required shade, gamut, sharpness, uniformity and, where applicable, white opacity.
• Hand and function: bending behavior, drape, surface friction, compression and any stretch or comfort requirement.
• Durability: acceptable dry and wet rubbing, laundering response and end-use performance.

The goal is a workable overlap between these targets. Raising solids until color stops improving can leave too much deposit for the fabric’s intended hand. Lowering solids until the fabric feels almost untreated can leave insufficient image control or durability. Neither endpoint defines an acceptable production specification on its own.

A useful practical distinction is between fixed ink input and matched final shade. First compare treatments at the same printer settings to understand their effect. Then, where the platform permits, optimize ink laydown to the same approved color. A treatment that improves color efficiency may allow a lower ink deposit, potentially changing the complete color–hand balance. That benefit must be measured, not assumed.

Design coverage matters as well. A small motif can feel acceptable while a large solid panel printed with the same chemistry feels restrictive. Include representative heavy-coverage areas and unprinted treated background in the evaluation, rather than approving a formulation from a small color swatch alone.

3. Calculate Actual Dry Add-On Before Adjusting Concentration

For a padding process, the estimated pretreatment deposit depends on both retained liquor and its solids concentration. Define the weighing basis consistently, especially when comparing fabrics with different moisture regain. The table below is a hypothetical mass-balance example for 150 g/m² dry fabric, not FSX test data or a recommended treatment range.

Wet pick-up (%) = retained treatment-liquor mass ÷ reference dry fabric mass × 100.

Estimated pretreatment dry add-on (% on dry fabric) = wet pick-up (%) × working-bath solids (%) ÷ 100.

Estimated dry deposit (g/m²) = fabric dry GSM × dry add-on (%) ÷ 100.

These estimates assume uniform liquor composition and representative retention. Starting moisture, selective uptake, drainage and application losses can introduce differences. For a gravimetric check, weigh comparable specimens using the same conditioning or validated dry-mass procedure before treatment and after drying, with replicate untreated and heat-only controls. Report the moisture basis and measurement uncertainty: a small mass increase can be obscured by moisture regain, and heating can also change the untreated fabric mass. The resulting weight gain represents total retained treatment residue, not binder content alone.

Trial	Wet pick-up	Bath solids	Dry add-on	Dry deposit	Approximate water retained
A	60%	3.0%	1.8%	2.7 g/m²	87.3 g/m²
B	80%	3.0%	2.4%	3.6 g/m²	116.4 g/m²
C	80%	2.25%	1.8%	2.7 g/m²	117.3 g/m²

Trials A and B use identical bath solids but leave different estimated deposits. Trials A and C leave the same estimated deposit with different water loads. They therefore cannot be assumed to dry identically or distribute the treatment in the same way. The calculation excludes initial fabric moisture and assumes water plus nonvolatile solids.

Translate supplied product dosage into working-bath solids

As an arithmetic example, 50 g of a product with 30% measured nonvolatile content contributes 15 g of residue to a final 1,000 g bath. Its contribution is 1.5% by mass before accounting for other ingredients. This does not establish how much of that residue is binder, nor does it recommend that concentration for printing.

For spray or coating, use the actual deposited wet mass per treated area: dry deposit (g/m²) = deposited liquid (g/m²) × bath solids fraction. Consumption from a spray tank is not identical to deposition because overspray and equipment losses may occur. Record garment treatment area and distinguish grams per garment from grams per square meter.

If dosage is stated in g/L while pick-up is measured by mass, use the bath density to make an accurate conversion. Also distinguish percentage of product as supplied from percentage active material. These small reporting differences can outweigh the apparent benefit of a modest formulation adjustment.

4. Same Solids and Same Viscosity Can Still Produce Different Hand

Total solids is a mass measure. Hand is the fabric’s mechanical and tactile response to the resulting deposit. Two treatments with equal dry add-on can differ because of polymer flexibility, adhesion, film continuity, ionic residue and the extent to which yarn movement is restricted.

A deposit concentrated at yarn intersections may influence bending differently from one spread along exposed fibers. A relatively continuous film can behave differently from a more localized deposit. For this reason, increasing surface holdout should be evaluated together with the resulting fabric mechanics, especially on lightweight apparel.

Binder flexibility is only one part of the decision

A softer film-forming polymer can be a useful candidate, but “soft binder” is not a complete performance specification. Investigate adhesion, rubbing resistance, tack, blocking, stretch response and the supplier’s curing requirements. A material that feels soft at room temperature may behave differently after laundering or during warm storage.

Research on a particular pectin-based conventional pigment-printing binder found that increasing binder concentration increased fabric bending stiffness while affecting rubbing performance. [3] This is evidence of a formulation-specific trade-off, not a basis for copying a screen-printing binder concentration into digital pretreatment or ranking all binder families.

Do not use viscosity as a proxy for solids

A small amount of an efficient rheology modifier can change viscosity substantially without an equivalent increase in total deposit. Conversely, a higher-solids dispersion can remain relatively fluid. The same Brookfield value can also conceal different shear response, recovery and wetting behavior.

Document the measurement concentration, hydration history, temperature, instrument, spindle and speed. Compare actual application consistency and print response alongside the reading. The FSX guide to thickener testing parameters can help structure material comparisons with clear test conditions.

Do not add textile thickener, binder or softener directly to a commercial pigment ink unless the ink manufacturer has explicitly engineered and approved that formulation. Pretreatment compatibility on fabric does not establish printhead compatibility, dispersion stability or reliable jetting.

5. Control Application Uniformity Before Raising the Average Dose

A fabric can have acceptable average pick-up but contain under-treated and over-treated areas. Increasing concentration to correct the pale areas can make the heavily treated regions stiffer. Map the distribution first, including left, center and right positions and samples taken at different points in the run.

Route	Main control question	Useful record	Hand-related risk to investigate
Padding	Is retained liquor uniform through width and time?	Pick-up, bath solids, tension and nip condition.	Full-width loading affecting unprinted background.
Coating	Is the deposited layer consistent on the intended face?	Wet mass per area, penetration and coating settings.	Localized film buildup or restricted drape.
Spray	Are coverage, overlap and deposited mass repeatable?	Nozzle output, area, passes and actual deposition.	Streaks, overlap bands or a visible treatment boundary.
Integrated digital application	Is the platform applying the specified treatment amount and pattern?	Calibrated laydown, treatment coverage and image settings.	Local buildup where treatment and ink coverage overlap.

Confirm whether the platform uses dried pretreatment or an integrated wet-on-wet sequence. These are different process architectures. Do not introduce an extra drying stage or substitute an offline bath simply because another pigment printing line uses one.

For garment printing, validate each relevant garment construction and supplier. Brother’s equipment guidance specifically recommends checking its diagnostic print on the garment brands being used, illustrating the need for substrate-specific qualification. [4] That guidance is platform-specific and should not be converted into a universal application volume.

Fabric preparation also matters. Uneven oil removal, residual softener, lint and variable surface absorbency can change deposition and image appearance. Compare a water-wetting screen with the actual treatment liquor rather than attributing every difference to solids. Keep print-side orientation and tension consistent.

For dark textiles using white ink, treat underbase loading as a separate variable. A white layer adds its own pigment and binder contribution and can dominate local hand. Optimizing pretreatment alone will not necessarily solve stiffness caused by excessive total ink film. Include opacity and color coverage when comparing lower-deposit candidates.

6. Separate Water Removal, Film Formation and Curing

Drying removes the liquid carrier; film formation establishes the polymer structure; curing may develop additional durability through the chemistry used by the system. These effects can overlap in time, but a dry-to-touch print is not evidence that its binder has reached the required performance.

Distinguish any pretreatment-drying step from the final printed-fabric cure. Record the sequence specified by the ink and pretreatment suppliers. In some systems, pretreatment preparation and final ink curing require different equipment conditions; integrated systems may use a different sequence entirely.

Use a validated thermal measurement approach appropriate to the line. Oven setpoint alone does not show how a wet, heavy fabric heats compared with a light fabric. Record loading, speed, airflow and residence time, then verify the condition experienced by the material. Keep the thermal record connected to the actual trial sample.

Do not soften the print by deliberately under-curing it

A lower thermal exposure may initially produce a softer feel while leaving inadequate durability or tack. Excessive exposure can also create unacceptable hand, shade or substrate changes. Establish a supplier-supported window and judge it using conditioned fabric and durability tests rather than a single touch immediately after the dryer.

Temperature and time are not freely interchangeable. Likewise, a binder’s minimum film-forming behavior does not by itself define the finished print’s full curing requirement. Request guidance for the supplied system rather than selecting conditions from an unrelated polymer datasheet.

Where a heat press is used, keep pressure, cover material and fabric positioning controlled. Pressure can change the surface appearance and texture independently of chemical loading. A glazed or flattened fabric can be perceived differently even when its pretreatment solids have not changed.

Most pigment routes rely on retaining a durable binding film rather than washing that film away. Do not introduce reactive-style wash-off or disperse reduction clearing as a routine softness correction. If a production wash or finishing step is part of the approved process, evaluate it explicitly; otherwise, laundering serves as an end-use validation stage.

7. Measure Fabric Hand as More Than “Soft” or “Hard”

Hand includes several sensations that can change independently. A fabric may have low surface friction but high bending stiffness, or feel flexible yet sticky. Ask the evaluator to identify the actual objection: boardy bending, roughness, rubbery surface, reduced compressibility, poor drape or resistance to stretch.

Property	Practical comparison	Important control
Bending stiffness	Use an appropriate bending-length or rigidity method.	Direction, specimen geometry and conditioning.
Drape	Compare representative panels using a repeatable setup.	Panel size, print coverage and fabric orientation.
Surface feel	Blind tactile assessment of roughness, friction and tack.	Same handling sequence and comparison standard.
Compression and fullness	Compare recovery after controlled compression where relevant.	Force, time and sample thickness.
Stretch and recovery	Measure extension and residual growth under a defined protocol.	Direction, load, recovery interval and print coverage.
Air permeability or wicking	Test separately when required by the end use.	Do not infer either property from softness alone.

ASTM D1388 describes fabric stiffness through bending length and flexural rigidity, while AATCC EP5 addresses consistent presentation and handling for subjective hand evaluation. [5] [6] Select the method appropriate to the construction and use the agreed edition and full procedure; these summaries are not substitutes for the methods.

Use stage controls to locate the source of stiffness

Retain an untreated fabric, a heat-only control, a pretreated unprinted sample taken through the complete thermal sequence, and the final printed sample. Also retain pretreated fabric before final curing if the workflow permits. These controls help distinguish substrate heating, pretreatment residue and ink-film effects.

Compare samples after the same cooling and conditioning interval. Add the agreed wash-and-dry sequence, then recondition and repeat the evaluation. Do not compare one hot sample with another stored overnight, or an unwashed print with a washed approval standard.

For a panel assessment, randomize sample labels and keep the evaluators unaware of dosage where practical. Use an approved fabric as an anchor and define descriptive scoring terms. Report disagreement as well as the average: a small numerical advantage may not be meaningful if assessors cannot distinguish the samples consistently.

8. Evaluate Color Yield, Sharpness and Durability Together

Use a diagnostic image with primary colors, mixed colors, dark solids, fine lines and unprinted gaps. Add a representative production design. For white-ink systems, include a controlled underbase pattern. Record print mode, ink limits, profiling conditions and any pretreatment laydown settings.

K/S can help compare apparent color strength on a controlled substrate, but it is not a direct pigment-adhesion or fixation measurement. Keep backing, orientation, instrument geometry and conditioning consistent. Opaque white layers, surface texture and changing scattering complicate comparisons, so also examine color difference, chroma and visual appearance.

Measure line width and boundary spread rather than relying only on an impression of sharpness. Compare solid-area uniformity and check whether stronger color is accompanied by mottling, pooling or visible treatment marks. For blends, inspect whether the different yarn components create an appearance the customer will accept.

Assess dry and wet rubbing separately. AATCC TM8 evaluates color transfer from a textile surface using controlled rubbing with dry and wet cloths. [7] Choose a suitable method for the print area, record the agreed conditions, and do not treat a dry-rub pass as evidence of acceptable wet rubbing.

Evaluate wash response using the buyer’s relevant protocol, including drying. Record shade change, staining, cracking, peeling and hand after laundering. A softer result after washing can reflect removal of unwanted residue, but it can also accompany loss of inadequately bound material. Softness improvement is only useful when the printed image and durability remain acceptable.

Set limits before looking at the candidate results. Use separate pass/fail gates for mandatory durability and functional requirements, then compare shade and hand among the candidates that pass. A weighted average score should not hide a failed rubbing requirement behind an attractive initial color.

9. Build a Trial Matrix That Separates Solids, Ink and Cure

The following sequence is a proposed development workflow, not a set of FSX test results. Start with a currently qualified recipe or the supplier’s recommended starting condition. Keep the fabric lot, printer condition and measurement methods controlled.

1. Define the target. Agree shade, coverage, hand, rubbing, laundering and any stretch or comfort requirements.
2. Identify the solids basis. Record supplied-product dosage, working-bath nonvolatile content and available information about functional components.
3. Measure application. Determine deposited wet mass and estimate dry add-on; map variation across the treated area.
4. Screen add-on. Compare lower, reference and higher levels within an appropriate supplier-supported range, keeping cure and ink input controlled.
5. Evaluate stages. Compare treated blanks and printed samples before and after the required thermal and laundering sequence.
6. Investigate chemistry if necessary. If every durable candidate feels unacceptable, review compatible formulation options rather than diluting indefinitely.
7. Confirm cure. Test justified conditions within the approved equipment and substrate limits.
8. Optimize ink to target shade. With a promising treatment selected, assess whether lower ink laydown can meet the same appearance and durability.
9. Repeat and scale. Confirm the operating range using independent bath preparations and representative production runs.

Trial result	Interpretation to investigate	Next useful comparison
Lower add-on passes all quality gates and feels better	The reference may contain avoidable deposit.	Repeat near the lower limit and test production variation.
Color improves but rubbing deteriorates	Placement and durable binding may be out of balance.	Check compatible binding and cure before adding more treatment.
Treated blank is stiff before ink application	Pretreatment deposit or its thermal response is implicated.	Compare add-on, distribution and compatible chemistry.
Blank is acceptable but dense print is stiff	Ink-film loading or the combined layer is implicated.	Compare matched-shade ink limits and white-underbase settings.
Softness improves only when durability fails	The tested range has no acceptable overlap.	Review the system rather than approving an under-performing compromise.

When changing the concentration of a complete commercial pretreatment, several functional ingredients change together. That trial evaluates product dosage; it does not isolate binder concentration. Make this distinction in the report so the observed effect is not assigned to the wrong ingredient.

If interactions between add-on and curing are important, use a small structured factorial design with repeated reference points. Avoid changing concentration, ink loading, softener and dryer speed simultaneously without a plan. The most useful trial explains why a candidate works and how much normal process variation it can tolerate.

10. Troubleshoot the Specific Failure Before Changing Solids

Symptom	Possible causes	First check	Avoid
Boardy treated background	Excess deposit, unsuitable film behavior or thermal effects.	Compare untreated, heat-only and treated blank controls.	Blaming pigment loading before testing the blank.
Strong color with poor wet rubbing	Surface pigment, weak binding or unsuitable cure.	Review curing and the complete ink–treatment combination.	Assuming additional solids will necessarily improve adhesion.
Soft fabric but weak, spreading image	Insufficient local treatment or incompatible wetting.	Map deposited mass and inspect dot spread.	Increasing every ingredient before checking distribution.
Patchy hand or rectangular marks	Uneven spray, overlap, residue, pressure or local heating.	Compare treated blanks and application patterns.	Correcting the average dose without checking local variation.
Tacky print or blocking	Residual carrier, incomplete cure or unsuitable film properties.	Separate drying, curing and storage-condition checks.	Adding softener as the first response.
Cracking during stretch	Excessive layer thickness or inadequate film extensibility.	Compare coverage and controlled extension after conditioning.	Accepting a static flat-fabric inspection.
Softer after washing but visibly faded	Loss of colorant or binding material as well as residue.	Measure shade change, staining and film integrity.	Reporting softness alone as an improvement.
Yellowing or surface glazing	Fabric, formulation or thermal/pressure incompatibility.	Use heat-only controls and inspect actual process conditions.	Compensating with more ink before finding the cause.

A compatible softener may be part of a qualified finishing system, but it is not a universal repair. Its ionic character, application stage and interaction with ink and binder matter. Any proposed addition should be checked for stability, shade, rubbing, wash response and required functionality. Apparent softness from lubrication does not demonstrate that excessive film buildup has been removed.

11. Validate the Production Window and Total Cost in Use

Choose an operating range that tolerates realistic variation in solids, pick-up, fabric supply and drying load. A recipe that passes only at a narrowly controlled laboratory point may not be practical across full-width production or repeated garment batches.

Sample after startup stabilization, during the run and following stops or replenishment. Track bath age, measured solids, viscosity where relevant, deposition and final fabric condition. Repeat checks on different fabric lots, especially when absorbency or finishing history varies. Document a response for drift instead of correcting by undocumented water or product additions.

Evaluate total cost per accepted square meter or garment. Include treatment consumption, ink, energy, line throughput, labor, rework, rejects and any finishing stage. Use the same artwork, shade and durability target. A cheaper treatment that needs more white ink or creates a higher reject rate may increase overall cost.

As a calculation example, reducing deposited solids from 3.6 to 2.7 g/m² lowers that deposit by 25%. It does not automatically lower treatment cost, drying energy or total printing cost by 25%. Equal dry deposit may involve different water loads, and different products may have different functional efficiency and purchase prices.

Environmental claims also require measured boundaries. Report water, energy or chemical changes against equivalent accepted output and the actual process stages included. A pigment route may avoid a production wash-off step, but that alone does not quantify the complete factory footprint or remove the need for laundering validation.

12. Frequently Asked Questions

1. Do higher pretreatment solids always improve pigment color yield?

No. Increasing treatment can improve ink placement within a useful range, but further addition may provide little color benefit or create unevenness, residue and hand problems. Compare deposited mass and finished results.

2. Is total solids the same as binder content?

No. Total nonvolatile material can include binder, rheology modifiers, ionic components and other additives. Obtain the relevant component information or application guidance before interpreting a solids result as binding capacity.

3. Can I judge solids from the bath viscosity?

No. Viscosity depends on polymer structure, concentration, temperature and measurement conditions. Two baths can have similar viscosity but different solids, and similar solids with different application behavior.

4. What is the ideal pretreatment dry add-on?

There is no universal value. Establish an operating range for the ink platform, fabric, application route and quality target. Qualify the lower practical range against variation rather than selecting the smallest laboratory dose.

5. Why does the same recipe feel stiffer on a lighter fabric?

Fabric construction and baseline flexibility change the perceived effect of a deposit. Compare both percentage add-on and grams per square meter, along with bending behavior and representative print coverage.

6. Should I reduce binder to improve softness?

Only after identifying where the binding function resides and testing durability. A change that improves hand but causes unacceptable rubbing or laundering performance is not a qualified improvement.

7. Can lower curing temperature make the print softer?

It may change initial feel, but it may also leave incomplete durability development. Use supplier-supported conditions and evaluate conditioned samples after the complete required performance tests.

8. Why can a deeper print have worse rubbing fastness?

More pigment may be retained near the surface without a corresponding improvement in secure binding. Color strength and rubbing transfer measure different outcomes and must be evaluated separately.

9. Can a softener solve excessive pretreatment stiffness?

A compatible finishing approach may help, but first identify excessive deposit, uneven application and curing issues. Recheck shade, rubbing and wash response after any change rather than approving tactile improvement alone.

10. Should pigment prints be washed after curing?

Follow the approved platform and product process. Many pigment routes do not need production wash-off. End-use laundering tests remain necessary, and a wash step should not be added simply to remove a required binding film.

11. Why must dark garments with white ink be tested separately?

The white underbase contributes additional material and changes the optical and mechanical structure of the print. Balance pretreatment with underbase opacity, color layers, hand and durability as one system.

12. What should I send for a pretreatment sample recommendation?

Start with fabric type, pigment ink or printer system and the main problem. A current pretreatment TDS and application record help define a useful comparison. Detailed trial conditions can follow once the route is confirmed.

13. Match Pretreatment to the Complete Pigment Printing System

Review the FSX digital printing pretreatment range for the relevant application route. Confirm the current grade and TDS with the actual pigment ink, binding system, fabric, application equipment and curing conditions before a production trial.

For sample matching and trial support, send your fabric type, pigment ink or printer system and main concern, such as stiff hand, weak color or poor wet rubbing. Include the current TDS and measured treatment add-on if available. Contact Service@fsxchemical.com to arrange the comparison.