scarlet red

scarlet red (countable and uncountable, plural scarlet reds)

1. Used other than figuratively or idiomatically: see scarlet,‎ red.
2. An azo dye used to treat wounds and ulcers and as a histological stain.
   • 2005, Avi Shai, Howard I. Maibach, Wound Healing and Ulcers of the Skin‎, page 219:

     Scarlet red is an aniline dye which has been used in the treatment of wounds and ulcers since the beginning of the past century.

   • 1959, Ivan Nikolaevič Filipév, Jacobus Hermanus Schuurmans Stekhoven, A Manual of Agricultural Helminthology‎, page 195:

     The staining may also be done in a saturated solution of scarlet red in equal parts of 70% alcohol and acetone....

• (azo dye): Biebrich red, Sudan IV

• scarlet red sulfonate