FAQs – Hydrochromic

Hydrochromic inks react to water or liquids by changing colour. We produce three variants:

1)  Irreversible Hydrochromic ink, changes from a solid colour to colourless when wet.
2)  Wet+Reveal ink is reversible, and starts white and becomes clear when wet, returning to white when dry again.
3)  Wash Off ink  is an opaque colour when printed , and dissolves and washes away under running water.

IRREVERSIBLE HYDROCHROMIC INKS & LABELS 

How does it work?

Exposure to water denatures the dye and the colour change becomes permanent if the water either washes the dye away or absorbs it into a paper substrate, or it does not dry out on top of the print. (These Irreversible hydrochromics can also be affected by high levels of humidity and are not suitable for exposure to such conditions).

What colours are available?

The irreversible hydrochromic inks are available in various colours: stock colours are black or blue.  Special colours are magenta, green, brown, orange, vermillion.

They have good colour strength.

What printing methods can I use?

Screen (water based) or flexo printing (water based or solvent based)

What substrates can I print onto?

Substrates used can affect the speed of response with ink printed on non-absorbent material generally changing more rapidly than on substrates such as paper. Colour reversion after drying out is more likely with prints on non-absorbent material than on paper though.

Can you produce labels for us using this ink?

Yes we can, on reels or on flat sheets.  Please contact to discuss this further.

WET & REVEAL INK

How does it work?

This is a water based screen ink which dries to give a white opaque print. When wet the ink film takes up water and becomes transparent allowing any print beneath to become visible. If the water dries out the opacity returns and the ink becomes white again.

What colours are available?
White.

What printing/coating methods can I use?

Screen printing (water based), or by using our sprayable ink.

I need to print onto board, how do I do it?

Wet and Reveal Screen ink can be printed on various substrates such as paper, cards, print receptive plastics and even textiles. Tests should be carried out to determine suitability for the substrate and application chosen.

How well does the ink cover a printed image underneath it?

A fairly heavy print is required, which essentially means the ink is supplied as a screen ink. More than one print may be required to obscure an underlying print. However as the coating weight of wet & reveal ink is increased the transparency when wet can be reduced so careful tests should be carried out to determine optimum printing parameters. Careful choice of underlying text / patterns can help by selecting something that will be easier to hide, such as images without large bold text or areas of substantial contrast.

Can I print onto material/textile?

We can supply a textile printable ink, but wet and reveal ink is not ideal for extremely stretchable material. Tests should be carried out to determine suitability for the substrate and application chosen. When a highly permanent print on textiles is required the dried wet and reveal print can be cross-linked by baking for 3 – 5 minutes at 130ºC.

Good results have been achieved with prints on absorbent substrates without additional curing but if a cross-linked film is desired, but if temperature treatment is not an option because of the choice of substrate, then chemical crosslinking agents such as aziridine may be employed.

Can you produce labels for us using this ink?

Yes we can, on reels or on flat sheets.  Please contact to discuss this further.

WASH OFF INK

How does it work?

This is a water based screen ink which dries to give an opaque colour. When washed or placed under running water the ink film dissolves and washes away allowing any print beneath to become visible.

What colours are available?

Colours available are black, navy blue, and white.   Other colours can be made on request with a higher MOQ.

What printing methods can I use?

A fairly heavy print is required, which means the ink is supplied as a screen ink.

I need to print onto board, how do I do it?

This ink is suitable for non-absorbent substrates such as plastic or board that has first been laminated.

How well does the ink cover a printed image underneath it?

Careful choice of underlying text / patterns can help by selecting something that will be easier to hide, so tests should be carried out to determine optimum printing parameters.

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