Technology of Daylight Fluorescent Colour
Swada’s Daylight Fluorescent Pigments and Inks can appear up to three times brighter than conventional pigments. Unlike some phosphors and other luminescent colours, both incident and emitted radiation are in visible spectrum, they are not dependent on UV (black) light and are not radioactive. Though Daylight Fluorescent colours may be enhanced by UV light they contain no inorganic phosphors (e.g. zinc sulphide) and do not "glow in the dark". They do however appear brighter than normal reflective colours in all daylight conditions and can be very effective in low-light conditions.
Daylight Fluorescence occurs when higher energy, short wavelength light is absorbed and instantaneously emitted at wavelengths longer than those of the absorption. This is known as Stokes Shift, defined as the separation (in nm) between the longest wavelength absorption band and the shortest wavelength fluorescence emission band. So, blue light is reflected as yellow or red light, yellow light is reflected as red light and the addition of the reflected light components can bring brightness up to three times as that of conventional pigments where a lot of the energy is merely absorbed.
Swada's Daylight pigments consist of a fluorescent dye dissolved in a solid polymer matrix. The polymer matrix can be thermoset or thermoplastic, depending on end use but in all cases the dye is fixed within the polymer, allowing it to be used in the manner of a traditional pigment.
Swada's liquid inks and concentrates are based on related polymer chemistry but the very finely divided fluorescent particles are formed within the ink medium maximizing the colour and brightness.
Dyes are used singly or in combination with other dyes and pigments to produce a range of bright colours across the spectrum. Please see our Colour Cards for details.