TT #71 · Parshas Tazria · Aliyah 1 · Passuk 2
English: When a person has on the skin of the body a swelling, a rash, or a discoloration, and it develops into a scaly affection on the skin of the body, it shall be reported to Aaron the priest or to one of his sons, the priests.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:2
Torah Temimah cites Sifra (Toras Kohanim) for assessing the appearance of an affliction in relation to the person’s own skin.
Sifra — Vayikra 13, Midrash Sefer
English: “On the skin of his flesh”—the appearance is judged against the person’s own complexion. The Sifra illustrates that a bright baheres may look faint against a German’s complexion (its example of light skin), while a faint one may look bright against a Cushite’s complexion (its example of dark skin).
Contextual qualification
The apparent intensity of a skin-affliction must be assessed against the person’s complexion; the same shade may look different against different skin tones.