The Physics of Sublimation
Sublimation is a phase transition, the direct conversion of a substance from solid to gas without passing through the liquid state. Water sublimates in this way when ice evaporates directly at very low temperatures and pressures. Dry ice (solid CO₂) sublimates at room temperature.
Sublimation dyes (disperse dyes) are engineered to sublime at 180–210°C, temperatures achievable with a heat press. At this temperature, the solid dye particles in the sublimation ink convert to gas. The gas molecules are small enough to penetrate into the open polymer matrix of polyester fibres at elevated temperature (heat opens the polymer chains). When the heat source is removed and the system cools, the polymer chains close and the dye molecules are trapped inside, they are no longer on the surface of the fibre, they are within it.
This is why sublimation is permanent in a way that surface printing is not. There is nothing to peel, crack, or wash away, the colour is inside the material.
The Polyester Rule · Non-Negotiable
This is absolute. Cotton fibres do not have the polymer structure that disperse dyes can penetrate and bond within. On 100% cotton, sublimation produces a faded, washed-out result with no durability, the dye sits on the surface and washes out immediately. On polyester blends, results are proportional to the polyester content. On 100% polyester, results are optimal.
The polyester rule applies to hard substrates too, mugs, phone cases, aluminium panels, and wood items that are marketed for sublimation have a polyester coating applied to their surface. The sublimation dye bonds into this coating. Remove the polyester coating and sublimation will not work on the base material.
Polyester content guide for sublimation results:
| Polyester content | Expected result | Suitability |
|---|---|---|
| 100% polyester | Vivid, full-saturation colour. Excellent wash fastness. | Optimal |
| 65% polyester / 35% cotton | Reasonable colour. Noticeable loss of saturation vs 100% poly. Moderate wash fastness. | Acceptable for some applications |
| 50/50 blend | Noticeably faded appearance. Heathered look where cotton fibres show as unprinted. | Poor, not recommended |
| 100% cotton | Near-invisible print. Washes out immediately. | Will not work |
The Two Sublimation Processes
Sublimation ink is printed onto special sublimation transfer paper using an inkjet printer loaded with sublimation inks. The printed paper is placed ink-face-down on the polyester substrate and passed through a heat press (flat press for garments and rigid items; calendar press for fabric yardage) at 180–210°C for 45–90 seconds. The sublimation occurs and the dye transfers from paper to substrate. Paper is then peeled away.
Sublimation ink is printed directly onto coated polyester fabric using a wide-format digital textile printer. The printed fabric then passes through a fixation unit (a heated calender roll) where sublimation occurs inline. Used for high-volume fabric production, soft signage, sportswear yardage, home textile, where the paper transfer method is too slow.
Critical parameters · heat press sublimation
| Parameter | Standard range | Effect of deviation |
|---|---|---|
| Temperature | 180–210°C | Too low: incomplete transfer, faded colour. Too high: colour bleed, burnt substrate on heat-sensitive materials. |
| Time | 45–90 seconds (flat press) | Too short: incomplete transfer. Too long: dye can re-sublime back into the paper (ghosting). |
| Pressure | Medium to firm (substrate-dependent) | Too light: incomplete contact, patchy transfer. Too heavy: deformation of 3D substrates. |
| Paper release | Peel hot or cold depending on substrate | Hot peel on fabric prevents ghosting. Cold peel on rigid substrates prevents paper bonding. |
Substrates for Sublimation
| Substrate | Polyester requirement | Typical applications |
|---|---|---|
| Polyester fabric (woven) | 100% polyester | Sportswear, soft signage, flags, banners, exhibition displays |
| Polyester fabric (knit) | 100% polyester | T-shirts, activewear (where polyester is specified) |
| Ceramic mugs | Polyester coating on ceramic | Promotional mugs, corporate gifts, photo mugs |
| Aluminium panels | Polyester coating on aluminium | Photo panels, wall art, awards |
| Phone cases | Polyester coating on polycarbonate | Custom phone cases |
| Mousepads | Polyester surface on neoprene base | Custom mousepads, desk accessories |
| Polyester coated wood | Polyester coating on MDF or wood | Personalised gifts, photo prints on wood |
| Polyester fabric flags | 100% polyester | Feather banners, pull-up banners, teardrop flags |
Applications
Dye Sublimation vs Other Decoration Methods
| Factor | Sublimation | Screen printing (plastisol) | DTG printing |
|---|---|---|---|
| Substrate | Polyester only | Cotton and blends | Cotton best |
| Colour vibrancy on polyester | Exceptional | Good | Good |
| Hand feel | Zero, dye is inside the fibre | Slight (ink on surface) | Minimal on good equipment |
| All-over (edge to edge) print | Yes, full bleed possible | Limited to print area | Limited to platen area |
| Dark fabric performance | Poor, dye is transparent; white polyester needed | Excellent with underbase | Good with white ink underbase |
| Minimum quantity | 1 piece | 24–48 pieces economically | 1 piece |
| Wash fastness | Excellent, permanent in fibre | Very good | Good with proper cure |
The critical dark fabric limitation: Sublimation dyes are transparent, they do not have sufficient opacity to show on dark polyester fabrics. For sublimation to work, the base fabric must be white or very light. This is why sublimated sportswear typically uses white base panels with sublimated colour areas, not fully dark garments.
Dye sublimation has two primary growth markets in India. The first is soft signage, fabric tension displays, exhibition backdrops, feather banners, and flags for the events, exhibition, and retail sectors. Every city with significant commercial or exhibition activity has sublimation printing capacity. The second is the gifting and promotional products market, sublimated mugs, photo panels, and merchandise are standard outputs from photo studios, gift shops, and corporate gifting companies across India. Equipment from Epson (SureColor F-series dedicated sublimation printers), Mimaki, and Roland dominates the market. For sportswear, Tirupur and Ludhiana have the highest concentration of sublimation printing for garment manufacturing, primarily for export orders for European and American sports brands that specify polyester performance fabrics.
Textile & Garment Printing, sublimation in context with other textile processes · Pad Printing, for 3D promotional objects · Specialty Substrates, fabric for signage