Lens-free technology allows standard transmissive substrates to be used rather than the specialist and expensive lensed substrates used for backlit applications.

"While it may cost €40 (£35.60) for a large sheet of lens, standard substrates for lens-free may be a quarter of that cost," said Positive Focus technical director Alan Dixon.

The use of standard substrates also allows recyclable materials to be used, which is becoming increasingly important.

"Print management companies are demanding recyclable substrates and everyone is looking for a USP," said Dixon.

The technique relies on the thickness of the material and separating the image into strips with one eye's image on the front of the substrate and the other on the back to create the 3D effect. The need to precisely register the front and back images requires the use of a UV-cured flatbed printer that has excellent repeatability. The need to print both sides also doubles production time.

One company that is using the lens-free technique is adapting it for short-life work by using adhesive clear film on the front and back sides of a clear sheet to enable graphics to be replaced frequently without the cost or disposal issues of replacing the entire sheet.

Positive Focus was exhibiting at Sign UK with Océ, which is one of a number of printer manufacturers it is partnering to promote the lenticular process. Dixon added that printers were increasingly seeing HumanEyes software as a relatively low-cost tool to provide a profitable application to complement the capabilities of new equipment.