Reflective & Retro-reflective materials in hi-vis workwear
Most surfaces have some degree of reflectivity but this is mostly diffuse
reflection. Diffuse reflection is where light hits a surface and scatters. The
disadvantage of this is that the reflection goes in many directions and breaks
apart into many wavelengths.
Hi-vis workwear additionally use retro-reflective materials, which are designed
to bounce most of the light back to its source instead of scattering it. There are two main technologies used, glass bead and prismatic.
Glass bead Available as a tape, and is quite inexpensive, but more of the light is lost internally in the bead, so less light is reflected back.
Prismatic Available as a vinyl tape, is more expensive but reflects back more light than the glass bead tape.