Our UV lamp for Alternative photography will expose A4 size prints evenly but there is a way to expose larger A3 size prints with two of these lamps.
Place two Lamps side by side with an approx. 2" gap between them to ensure full and even exposure of your A3 size coated paper. We recommend an exposure time of around 15 minutes to expose fully.
Below is the finished print, it was exposed as explained and illustrated above, it is fully exposed no banding in the middle or vignetting on the corners.