Is UV Printing Food Safe? The Ink on a Gahwa Cup, the Rim and the Dishwasher

Short answer: the UV ink on a printed gahwa cup is a decoration on the outside of the cup, not a food-contact layer, so it should never touch the coffee and should stay off the rim. At Sun Studio Dubai we print the outside wall only, leave the inside of the cup bare, and keep the design off the rim where lips rest. We do not call a UV-printed cup 'food safe' or 'dishwasher safe', because no single label makes a printed cup either. This guide explains why, and what to ask for instead.

At a glance:

• Where the ink goes: the outside wall of the cup, below the rim. Never the inside, never the rim edge.
• What the ink is: UV-curable inkjet ink, cured hard by UV light on the press. It is not edible ink and not a kiln-fired ceramic decoration.
• Food-contact claim: none. We make no food-contact claim for printed glass or ceramic.
• Documents: the ink's safety data sheet on request.
• Washing: in our own tests, prints on porcelain gahwa cups lasted more than 60 dishwasher cycles in home and commercial machines. We still do not call them dishwasher safe.
• Press: an LSINC PeriQ360 cylindrical UV printer, supplied and supported in the region by PRO TECHnology.

Is UV ink food safe?

Not in the way the question is usually meant. 'Food safe' is not a label an ink carries on its own: food-contact rules judge the finished article in the way it is used, and an ink printed on the outside of a cup is not meant to be a food-contact surface at all. The basic rule is the same in the EU and in Dubai: a material that touches food must not pass its own ingredients into the food in amounts that could harm health. It is written in Article 3 of EU Regulation 1935/2004, and Dubai Municipality's technical guidelines for food contact materials (2024) uses the same test and names ceramics, glass and printing inks among the materials it covers. Across the Gulf, GSO 2231 sets the general requirements for materials that touch food.

Inks get their own rules only in a few places. The European printing ink association EuPIA notes that there is still no EU-wide law listing approved inks for food-contact materials. Switzerland keeps a list of assessed ink substances, and it covers inks printed on the side of a package that does not touch the food. UV inks harden because of photoinitiators, and the European Food Safety Authority has said it does not want two of them, ITX and 4-methylbenzophenone, both used in inks on food packaging, getting into food. That is why the industry's suitability list for UV ink is written for the side that faces away from the food, and why a decorator should keep it there.

So the useful question is not 'is the ink food safe?' but 'does the ink stay out of the cup and off the rim?' On a gahwa cup printed the way we print it, it does: the coffee only ever touches the cup's own glaze, and the rim is left bare. The ink documents are there for buyers whose own food-safety plan asks for them.

Where the ink sits on a printed gahwa cup

A finjan has no handle, so the hand holds the lower wall, the lips meet the rim, and the coffee fills the bowl. Each of those decides where ink may go:

• Inside: never printed. The coffee touches nothing but the cup's glaze.
• Rim: left clear. Lips rest there, and it is also where cloths and dishwasher racks wear a cup first.
• Outside wall: the printed area. Colour, white ink, fine linework and full designs all sit here.
• Foot: left clear, because it rubs on trays and on the cup below it in a stack.

Rules for decorated drinking vessels treat the outside band just below the rim as a zone of its own, because that is where lips land. Canada's glazed ceramics and glassware regulations, for example, set lead and cadmium limits for any drinking vessel with a decorative pattern 'within 20 mm of the rim'. Those limits were written for kiln-fired glass and ceramic enamels, not for UV ink, but they show where the mouth meets the cup. A design that covers the whole wall, like the maroon cup below, still stops at the rim. For cups that will be used every day in a majlis or a hotel rather than kept as a gift, we can set the design lower and leave a wider plain band under the rim.

UV print, fired decoration or a plain cup: which to choose when food contact matters

Direct UV printing suits gifts, events and branded sets, and any order where every cup carries a different name. When a buyer needs a test report on the finished, decorated cup, a kiln-fired decoration ordered through the cup maker is the route that comes with one.

Lead and cadmium are what the existing tests for decorated drinkware look for. The EU directive on ceramic articles fills the cup and measures what comes out of the surfaces food touches; the US FDA's lead guidance does the same for ceramic foodware; ASTM C927 checks the lip and rim area of drinking glasses decorated outside with fired enamels. None of them was written for an organic UV ink. A lead and cadmium report is a document for the cup and for fired decoration; for a UV print, the document that applies is the ink's safety data sheet.

Is a printed gahwa cup dishwasher safe?

We do not call it dishwasher safe. In our own wash tests, prints on porcelain gahwa cups lasted more than 60 dishwasher cycles in home and commercial machines. That is our result on our cups and our print build, not a rating for yours, and the same applies to the questions people ask about printed mugs and tumblers.

No single test makes a print dishwasher safe. The European standards for the dishwashing resistance of tableware, the EN 12875 series, check how an article looks after repeated washing, and the first part says it does not define how many cycles a product has to withstand. They test durability, not food safety. A commercial machine in a hotel or cafe is harder on a cup than a home one, and the rim and the foot wear first. How to wash printed cups, how to test a sample before a run and how to match broken cups later are covered in our guide to dishwasher and scratch resistance of printed gahwa cups.

Microwave: we do not rate printed cups for the microwave. A gold or silver rim rules a cup out of the microwave whatever the print does, so follow the cup maker's label.

How we print gahwa cups on the LSINC PeriQ360

Gahwa cups go through three stages in our studio in Al Quoz:

1. Preparation. Each cup is cleaned, and pre-treated where the glaze calls for it, with plasma or Pyrosil among the treatments, so the ink bonds to the surface. Ink adhesion and pre-treatment explains why.
2. Print. The cup goes on the LSINC PeriQ360, a cylindrical UV printer with four spindles that holds each cup on its axis and wraps the design all the way round, so a repeating pattern has no visible join. White ink goes down first where the colour has to stay bright on a coloured ground.
3. Cure and check. UV light cures the ink as it prints, with a clear varnish where specified. A sample cup is approved before the run.

The PeriQ360 is made by LSINC, the US maker of the Peri series, and supplied, installed and supported in the region by PRO TECHnology, LSINC's exclusive distributor for the Middle East and North Africa since 7 December 2023. PRO TECHnology belongs to the same Dubai group as Sun Studio, so read our view of the machine with that in mind. Its own notes on what LSINC printers print say the same thing we do: the print is a decoration on the outside of the container, and food-contact use needs the ink's documents checked. Our PeriQ360 explainer covers the press in more detail.

What to ask before you buy printed cups for serving

1. Where does the ink go? Outside wall only, with the inside and the rim left bare.
2. Can I see the ink documents? Ask for the ink's safety data sheet if your food-safety plan needs it.
3. Who made the cup? The glaze, and any gold or silver rim, belong to the cup maker, and so do its own food-contact documents.
4. Will you wash a sample my way? A sample cup through your own machine and detergent is a better test than any claim.
5. Do I need a test report on the finished cup? If yes, choose fired decoration through the cup maker. If no, direct UV print gives you more design for fewer cups.

Printed gahwa cups for the majlis, hotels and gifting

Many of the gahwa cups we print are gifts: corporate sets for Ramadan and National Day, wedding favours, and branded cups for events. Sizes, sets and where a logo sits on a curved cup are covered in our gahwa cup guide. Recent work includes 300 printed gahwa cups in five designs for a client in Qatar and one hundred printed gahwa cups as wedding favours. For a corporate order, see corporate gift printing in Dubai; for bottles, tumblers and other round items, cylindrical printing.

Anything meant to be eaten is a different process: chocolate and macarons are printed with edible ink on a dedicated food printer, as described on food printing in Dubai.

Common questions

Send a photo of your cups and the design, by WhatsApp or phone on +971 4 346 7422, or by email to info@sunstudio.ae. Sun Studio Dubai has been printing in Al Quoz First since 2011, with no minimum order. Ask for the ink documents with your quote.