Definition of lightfast in English:

lightfast

adjective

  • (of a dye or pigment) not prone to discolour when exposed to light.

    ‘colour it with a lightfast paint’
    • ‘The Bisphenol A bischloroformate is then reacted with another chemical to produce a lightfast epoxy resin.’
    • ‘I was wondering if anyone knows whether its nupastels are lightfast or not.’
    • ‘Need the right expert in lightfast dye?’

Pronunciation

lightfast

/ˈlʌɪtfɑːst/