How to Screen Print Thermochromic Ink
Thermochromic ink changes colour with temperature. SFXC® thermochromic screen inks show their colour below the activation temperature and turn translucent above it. As the print returns to its starting temperature, the colour comes back, so the effect can be repeated again and again. This guide covers how to get a clean, reliable colour change with our water-based thermochromic screen inks on paper, board and fabric.
1. Choose your temperature
| Temperature | What happens | Colours |
|
Chill & Reveal 15°C (59°F) |
Colour shows below 15°C and fades as it warms above it | Blue, Black |
|
Touch & Reveal 28°C (82.4°F) |
Colour fades with the warmth of a hand or breath, and returns as it cools | Black, Blue, Red, Magenta, Yellow, Green, Purple, Orange, plus colour-to-colour: Blue to Green, Purple to Pink, Orange to Yellow, Gold to Silver Metallic |
|
Heat & Reveal 45°C (113°F) |
Colour fades with heat, such as a hot drink or hot water, and returns as it cools | Black, Red |
The colour change happens over a few degrees: the colour starts to fade at about the stated temperature and is fully translucent a few degrees above it.
Need a different colour or temperature? As well as the colours above, we can supply other thermochromic colours and activation temperatures to order. Contact us with the colour, temperature and quantity you need, and we'll confirm availability, lead time and any minimum order.
The colour fades to translucent, not completely clear, so a faint trace of the colour may remain above the activation temperature.
2. Choose your material
- Paper and board: absorbent paper and board give the best results. Suits cards, packaging, labels, posters and promotional items.
- Fabric and textiles: the same ink system prints onto fabric. Keep heat to a minimum when drying (see section 5), and test washing on your own fabric before a production run.
- Other materials (plastics, films, glass, ceramics): contact us before use.
If you're not sure, start with a 100 ml size and test it on the exact material you'll use.
Specifications at a glance
| Effect | Reversible: colour below the activation temperature, translucent above |
| Ink system | Two-part, water-based: thermochromic slurry + SFXC® Soft Base binder |
| Mixing ratio | Slurry and binder, 50/50 |
| Application | Screen printing; foam roller for small projects |
| Heat limit | Below 180°C, as briefly as possible; avoid prolonged exposure above 75°C |
| Light fastness | Grade 1: not for long outdoor exposure |
| Storage | Cool and dark, 20°C or below, tightly closed |
| Best used within | 12 months |
3. Mix before use
- Stir the thermochromic slurry thoroughly.
- Mix equal amounts of slurry and Soft Base binder (50/50) until the colour is even.
- Use each thermochromic colour on its own. Mixing or layering thermochromic colours can weaken the colour change.
- Don't thin with alcohols or acetone (methanol, ethanol, acetone). The thermochromic microcapsules are sensitive to these solvents.
4. Print in thin, even coats
- Make sure the surface is clean, dry and free from dust or grease.
- Screen printing gives the most professional result. For smaller or simpler projects, a foam roller can be used.
- Avoid brushes. A brush leaves an uneven layer and reduces the clarity of the colour change.
- Apply 2–3 thin, even coats rather than one heavy one.
- The best mesh and number of passes depend on your material and design, so run a test print first.
5. Dry gently: keep the heat low and short
Heat is the main thing to watch. Thermochromic ink reacts to temperature by design, and too much heat damages it.
- Keep any drying or processing heat below 180°C, and as short as possible. Higher temperatures reduce colour strength and weaken the colour change.
- Avoid prolonged exposure above 75°C. The thermochromic components may break down above 80°C.
- Brief heat at 100°C for 1–2 minutes is acceptable.
- On fabric, keep any heat pressing or tunnel drying as short as possible within these limits.
Test your own material through the drying process before a full run.
6. Test the colour change
Once dry, check the effect: touch it with a warm hand (Touch & Reveal, 28°C), apply hot water or a warm surface (Heat & Reveal, 45°C), or chill it below 15°C to bring the colour out (Chill & Reveal, 15°C), and watch the colour change and return. Repeat a few times to check it performs the way your product will be used.
What thermochromic ink can't do
- Long exposure to sunlight. UV light breaks down the colour-change effect; in strong sunlight it can deteriorate within several hours. It isn't suitable for outdoor use.
- Solvents. Alcohols and acetone damage the microcapsules.
- Mixing colours. Mixing or layering thermochromic colours weakens the effect.
- Becoming fully clear. Above the activation temperature it turns translucent, not invisible.
- Skin, food or cosmetics. It isn't intended for cosmetics, use on skin, or anything that comes into contact with food.
Troubleshooting
- Weak or dull colour change: usually too much heat during drying, or the ink was mixed with another colour or contaminated with solvent. Check the heat limits in section 5.
- Uneven or streaky colour: a brush was used, or the coat is too heavy. Use a screen or foam roller and thin coats.
- The effect fades over time: UV light or sunlight exposure. Keep printed items out of strong sunlight.
- The effect is weaker from a stored pot: old stock, or stored too warm. Store at 20°C or below and use within 12 months.
Caring for printed items
We don't have wash-fastness data for printed fabrics, so test washing on your own fabric first. We recommend a cool, gentle wash, inside out, and avoid tumble drying or ironing over the print, since heat damages the effect.
Storage, shelf life and cleaning
- Store in a cool, dark place, at 20°C or below, with containers tightly closed.
- For best results, use within 12 months.
- The colour change can weaken after long exposure to UV light, acid or humidity.
- Clean screens and tools with water straight after printing.
Handling
The thermochromic slurry is classified as harmful if swallowed and as a skin and eye irritant. Wear gloves and eye protection, don't eat, drink or smoke while using it, and wash your hands after handling. The Soft Base binder isn't classified as hazardous. See the Safety Data Sheets for full details.
Moving from testing to production
We supply individual makers, printers and businesses worldwide. Our 100 ml size is designed for testing. Once you're happy with the result, the inks are available in 1 litre, with larger quantities on request. We can also supply other colours and activation temperatures to order. Contact us with your application and quantities and we'll confirm suitability and lead time.
Our team has over 20 years' experience with colour-changing materials, including supplying the inks for, and technical guidance on, a colour-changing floor installation at Tate Modern.
Before use: please read the Technical Data Sheet (TDS) and Safety Data Sheets (SDS), and always test on your own material before a print run or production.
See TDS information (Revision 5, October 2026) | See SDS information – thermochromic slurry (Version 6.0.0, October 2026) | See SDS information – Soft Base binder (Version 4.0.0)