lightfast

light +‎ fast

• (US) IPA^(key): /ˈlaɪtfæst/
• Hyphenation: light‧fast

lightfast (comparative more lightfast, superlative most lightfast)

1. Resistant to fading.

   Verdigris is lightfast in oil paint, as numerous examples of fifteenth-century paintings show.

   • 2004, Peter K. Burian, Masteringdigital Photography and Imaging, page 75,

     Some ink-and-paper combinations are more lightfast than others, and the resulting prints are more fade-resistant.

   • 2009, Anthony Covington, Tony Covington, Tanning Chemistry: The Science of Leather, page 286,

     Tara, a gallotannin, is often quoted as being the most lightfast vegetable tannin and makes very pale coloured leather.

   • 2010, Sherry Stone Clifton, Anita Marie Giddings, Pastels For Dummies, unnumbered page,

     The blue, or cyan, is the most lightfast ink used in the printing process, so it lasts the longest. That blue, incidentally, is the phthalocyanine blue pigment.

     You can easily test to determine whether any material is lightfast.

• (resistant to fading): colorfast

• lightfastness