The purpose of this study is to learn more about the potential effects of visible light on the skin. More specifically, this study will examine whether an incandescent lamp (light bulb) or LED light bulb can cause skin to become darker. Investigators will determine the minimum threshold dose required to achieve immediate pigmentation darkening (IPD), persistent pigmentation darkening (PPD), and delayed tanning (DT) for Fitzpatrick skin types IV - VI utilizing two visible light sources.

Inclusion Criteria:

• Be a healthy volunteer with Fitzpatrick skin types I-VI;
• Agree to abide by the Investigator's guidelines regarding photosensitizing drugs and photoprotection;
• Be able to understand the requirements of the study, the risks involved, and be able to sign the informed consent form;
• Agree to follow and undergo all study-related procedures.

Exclusion Criteria:

• Women who are lactating, pregnant, or planning to become pregnant;
• Patients with a recent history of vitiligo, melasma, and other disorders of pigmentation with the exception of post-inflammatory hyperpigmentation;
• Patients with a known history of photosensitivity disorders;
• Photosensitizing medications may be continued throughout of the study at the discretion of the investigator ;
• Patients with a known history of melanoma or non-melanoma skin cancers;
• Concomitant use of tanning beds;
• Sun exposure of the irradiated or control areas;
• Patients with serious systemic disease.
• Patients with a known history of hypersensitivity to adhesives including adhesive tape.