sciencesoup:

Lighting up the Skin

Humans have practiced tattooing for thousands of years, but recently many people have been seeking subtler types that can’t be seen in normal light, such as glow-in-the-dark or Ultra Violet tattoos. While traditional tattoo ink consists of metallic pigments combined with a carrier solution, glow-in-the-dark ink utilises the process of phosphorescence, absorbing light and later emitting it as a glow in darkened conditions. UV ink, on the other hand, utilises the process of fluorescence and can only be seen under a blacklight—highly energetic UV light that lies just above visible light on the electromagnetic spectrum (i.e. just above violet). Fluorescent substances absorb this light and then re-emit it, and because some energy is lost in the process, the re-emitted light has a longer wavelength and so becomes visible. The vibrancy of UV tattoo ink depends on the colour, and the tattoos are nearly invisible in normal light, although scarring from the application process can still show. Dozens of everyday materials produce a fluorescent glow such as soda, detergents, and white paper—so it’s perhaps unsurprising that while there are safety concerns over phosphorous inks, UV inks seem to be far safer. However, they do currently have a reputation for irritation and complications, so the process is far from perfect just yet—but it looks awesome.

vlynx:

Camille Seaman