Duratrans is a brand name which basically designates a traditional colour photographic printing process (film) on a large format medium (photo paper) specially made to be backlit and inserted in a lightbox between a transparent anti-glare protective film and a white light-diffusing backing.
But that was before! That was when you had time to send your film to the lab to be developed and wait for the print to be delivered by courier or post…
In the age of digital printing, we talk about 4-colour printing on light-diffusing polyester film. In this case, the 4-colour printing is intensified (double-pass printing) so that it is magnified and not washed out by the backlighting.
The backing is usually a backlight or backlit polyester film specially designed for this purpose.