How to Screen Print Hydrochromic Ink

Hydrochromic ink is white when dry and turns see-through when wet, revealing whatever is printed underneath. As it dries, the white returns, so the reveal can be repeated again and again. This guide covers how to get a clean, reliable wet-and-reveal effect with SFXC® hydrochromic screen-printing inks, whether you're printing a test piece or a production run.

Hydrochromic ink or hydrochromic paint?

Many people search for "hydrochromic paint", but our hydrochromic materials are made for screen printing or spraying, not brushing. A brush leaves the coat too thick and uneven, and the white won't clear properly when wet. For small or awkward areas, use a flat foam roller with the excess removed. For large or uneven surfaces, use our sprayable hydrochromic ink, which goes through standard spray equipment or an airbrush. Browse the full range of hydrochromic inks, sprayable ink and Wet & Reveal film.

1. Choose the right ink for your material

All are water-based and reversible. If you're not sure which suits your material, start with a 100 ml size and test it on the exact material you'll use in production.

2. Plan your design: the hydrochromic layer goes on top

Print your hidden message, image or colour first, then print the hydrochromic ink over it as the top layer. When dry, the white hides what's underneath. When wet, it turns clear and the design shows through.

Choose light colours for the hidden layer. Hydrochromic ink is white, so it hides light colours best. Strong dark colours such as black, dark blue or red can show through the white even when dry. Use lighter versions instead (grey, light blue or pink) for the cleanest reveal.

3. Prepare your screen

  • Recommended mesh: 77T (196 threads per inch). Don't go finer than 90T (229).
  • The mesh controls how much ink goes down. More ink gives a whiter, more opaque cover when dry. Too much stops it clearing properly when wet. 77T gives the best balance between the two.
  • The hidden print underneath must be fully dry before you print the hydrochromic layer over it.

4. Mix before use

The ink can settle in transit, so stir it thoroughly before use, ideally with a mechanical stirrer. Don't mix it with other inks.

5. Print in thin passes

  • Print thin passes rather than one heavy coat. A coat that's too thick, or too many layers, stays cloudy when wet and spoils the reveal.
  • Where you need a stronger white, add a second or third pass, letting each dry first.
  • Don't let ink sit unused on the screen. It dries into the mesh and spoils the print quality.
  • Typical consumption is about 30–35 g per square metre.

6. Dry and cure

The ink air-dries, or you can speed it up with IR lamps or hot air. To fully cure it, so it bonds properly and stands up to repeated wetting, bake it at 130°C for about 3 minutes. For the best adhesion and water resistance, up to 130–150°C for 3–5 minutes. Not every material tolerates that heat, so test your own material through the baking process before a full run.

7. Test the reveal

Once cured, wet a small area with water. The white should clear evenly and the design should show through. Let it dry and check the white returns. If the reveal is patchy or the white looks thin, see the troubleshooting section below.

Troubleshooting

  • The hidden design shows through when dry: the colour underneath is too dark. Lighten it, or add a further thin pass of hydrochromic ink.
  • The white doesn't clear fully when wet: the coat is too thick. Use thinner passes, or a finer mesh, up to 90T.
  • Patchy white: the coverage is uneven. Print another thin pass.

Caring for printed items

For printed textiles, we recommend a cool wash.

Storage, shelf life and cleaning

  • Shelf life is 6 months.
  • Store away from frost and heat, and not above 25°C.
  • Keep the container tightly closed. Being water-based, the ink skins and thickens if air gets in.
  • Clean screens and tools with water straight after printing. Don't let ink dry in the mesh.

Moving from testing to production

Our 100 ml size is designed for testing. Once you're happy with the result, the inks are available in 1 litre and 5 litre sizes, with larger quantities made to order. We can also supply irreversible hydrochromic inks in black or blue, inks for flexographic and offset printing, and custom formulations. Contact us with your application and quantities and we'll advise on the right option, lead time and minimum order.

Our team has over 20 years' experience with colour-changing materials, backed by technical support from our manufacturing partners.

Before use: please read the Technical Data Sheet (TDS) and Safety Data Sheet (SDS), and always test on your own material before a print run or production.

Shop hydrochromic inks, sprayable ink and Wet & Reveal film →