UV Day Light In a Box
UV Day Light In a Box 4
Inventor William Murdoch
Ultraviolet Light Box first created and used by Murdoch in Snakes and Ladders to find blood residue on various different items. That handy box has come in use on many cases, notably in Murdoch Night in Canada.

In the Season 10 (ep.1003), the Ultraviolet Light Box is up-graded to a hand held light (Torch or Flashlight).

In Season 11 (ep.1106), George Crabtree improvises making a UV torch with a petri dish, some glue and violet phosphorous in the chemistry lab of Laird College: "I am illuminating the invisible. Violet phosphorous absorbs visible light and translates it into ultraviolet radiation. At least, I think that's how the Detective put it."


The interaction of light with matter has attracted attention for centuries. First, mathematician and astronomer Claudius Ptolemy (100–170) defined the refraction of light in objects. In 1305, theologian and physicist Theodoric of Freiberg (1250–1310) created a simulation rainbow with water-filled glass spheres. In the 1800s, British astronomer Frederick William Herschel (1738–1822) discovered radiation in sunlight by passing it through a prism.

Electromagnetic radiation comes from the sun and transmitted in waves or particles at different wavelengths and frequencies. This broad range of wavelengths is known as the electromagnetic (EM) spectrum. The spectrum is generally divided into seven regions in order of decreasing wavelength and increasing energy and frequency. The common designations are radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.

Certain materials possess a property called Fluorescence: when light of a particular color and frequency strikes an object, and the object returns light of a different color and frequency. The real science and forensics of Fluorescence: Blood does not fluoresce by applying UV or visible blue light; It can be made to “glow in the dark” by spraying certain chemicals such as Luminol, BlueStar or Fluorescene on the various surface — and adding blue light is not necessary. On the other hand, UV (alternate) light sources can reveal the following: seminal fluid, saliva, urine stains and certain narcotics, as well as bone and teeth fragments.

Thus William Murdoch's invention is quite extra-ordinary as it bypasses the need for chemical applications or any filtration that blocks the visible light but passes the fluorescence – in Murdoch's world.

Appearances and Mentions


Community content is available under CC-BY-SA unless otherwise noted.