Optical brighteners are actually fluorescent dyes that brighten color of
the fiber. However, ultraviolet light from the sun may cause these dyes
to exhibit a lavender cast in areas where the solution has been used. These
dyes can eventually oxidize, causing a yellow discoloration on the fiber.
Once applied, optical brighteners are hard to remove. Fabpro does
not use any optical brighteners in their products. Use heat transfer method
using Fabpro's Neutral Prespray and soil remover at 1:1 dilution to remove
offending optical brighteners.