What did the job entail?

Reading-headquartered print finisher Celloglas applied a range of special finishes, including heat-reactive ink, to the cover, which was printed CMYK with a special gold Pantone. Heat-reactive, or thermochromic, ink can be used to reveal hidden information, such as marketing messages with added interaction or answers to quiz questions, at a range of temperatures.

How was it produced?

The cover was created by producing a solid black, white and gold image in the top area, bottom banner and the centre image, then printing a pattern of images to be revealed under a layer of black heat-reactive ink. 

Celloglas finished 12,426 copies of the cover, which were initially printed by West Midlands-based William Gibbons using Precision Special Gloss 250gsm stock. Celloglas then applied the heat-reactive ink on top of the printed sheets at its Leicester site using a Sakurai Silkscreen press. The cover was also matt laminated using an Ecotack laminator to protect the thermochromic ink (as readers interact with it) and to provide a smooth matt-effect finish. 

Celloglas sales director Steve Middleton said: “It’s always a pleasure to use our decorative finishes in such an inventive way. This cover demonstrates how the use of interactive finishes can really increase reader engagement.”

What challenges were overcome?

The thermochromic ink had to cover a large area so the job had to be run carefully to ensure a smooth application.

What was the feedback?

Many of the magazine’s readers posted images on social media showing how they revealed the hidden text and images by using methods including a hair dryer, a cup of hot coffee, warm hands and a hot water bottle. Computer Arts editor Nick Carson said: “Our cover designers always get very excited to work with Celloglas decorative finishes and this cover is no exception, it could be our most innovative yet.”