A new process is presented to non-invasively identify organic dyes in
historic textiles and other works of art. A small gel bead loaded with a
SERS substrate is used to gently extract microscopic amounts of dyes from
works of art, without the need to remove a sample and separately extract
the dye by acid hydrolysis of the fiber-mordant-dye system. The gel bead
subsequently is coated with a silver, gold or copper colloid or with
silver, gold or copper nanoislands, and is examined in accordance with a
surface enhanced Raman scattering technique to identify the dye.