In physics, an object is considered dark when it absorbs photons, appearing dim compared to other objects. Matte black paint, for example, absorbs much visible light and appears dark, while white paint reflects light and appears bright. Exposure to alternating light and darkness, like night and day, has caused evolutionary adaptations; a human entering a dark area will experience pupil dilation to allow more light into the eye. Additionally, light-detecting cells regenerate unbleached rhodopsin when adapting to darkness.
One scientific measure of darkness is the Bortle scale, which indicates the brightness of the night sky and the observability of celestial objects. Vantablack is one of the darkest substances known, absorbing up to 99.965% of visible light, and was developed by Surrey NanoSystems in the United Kingdom.
On a standard 24-bit computer display, color is defined by RGB values ranging from 0–255. A pixel appears black when all three components are unilluminated (0,0,0), and white when fully illuminated (255,255,255).
In the Judeo-Christian tradition, the creation narrative begins with a void described as “formless and empty,” with “darkness was over the surface of the deep” (Genesis 1:2). God then introduces light, declaring, “Let there be light” (Genesis 1:3). Light is often associated with divine presence and goodness, while darkness symbolizes ignorance and sin. In Exodus 10:21, darkness is described as a plague upon Egypt, representing both physical and spiritual blindness.
In Islam, light (nūr) and darkness (ẓulumāt) are invoked in both physical and spiritual contexts. The Quran begins with Allah creating “the darknesses and the light” (Quran 6:1). Believers are described as being “brought out from darkness into light” (Quran 2:257), a metaphor for a journey from ignorance to divine knowledge.
In ancient Greek mythology, Erebus was a primordial deity representing darkness, particularly associated with the realm of death and the underworld. Darkness in Greek cosmology was not merely an absence of light but an active force linked to the afterlife.
As a poetic term, darkness is used to connote shadows, evil, and foreboding, or to convey a grim or depressing tone. William Shakespeare referred to a “prince of darkness” (King Lear: III, iv) and gave darkness jaws with which to devour love (A Midsummer Night’s Dream: I, i). Geoffrey Chaucer wrote that knights must cast away the “workes of darkness,” and Dante described hell as “solid darkness stain’d” in Divine Comedy.
In Old English, three words could mean darkness: heolstor, genip, and sceadu. Heolstor also meant "hiding-place" and became holster. Genip meant "mist" and fell out of use, though it remains in the Dutch saying "in het geniep" which means secretly. Sceadu meant "shadow" and remained in use. The word dark eventually evolved from the word deorc.