When the design was created it was intended that the print would use white ink on black paper. In the first printing session the design was printed using white ink, however there were a few complications. White screenprinting ink is the fastest drying ink because it has much larger molecules of pigment than other colours, and as the detail in the design contains many fine lines, the screen clogged quickly and prevented the print from being pulled through cleanly every time.
Despite pulling the prints through at a faster speed and washing the screen between pulls, the prints were still patchy. To resolve this, a new colour scheme of black ink on red and black papers was trialled. These colours were still appropriate for the brief as traditionally when x-rays are depicted in a scientific context, the colour red is used to indicate the waves. The print on red card also created a high impact design. X-rays are also invisible to the eye and so a black on black print created a unique 'invisible' effect. This could also be enhanced by printing an extra layer of glow-in-the-dark ink over the top of the original design to create a second hidden layer.
These alternative prints pulled through far easier, however after gaining feedback from peers it was concluded that the white ink on black paper created the most visually striking and appropriate print. It was also noted that the slight misprint around the edges of the poster enhanced the traditionally printed nature of the poster, creating an additionally worn and aged aesthetic.