Dermatologic Photography of Nail Pathologies

Abstract

Professional-quality photography of nail pathologies can easily be a routine in a dermatologist's office with the use of modern equipment for a camera system. The camera body component should be a single-lens reflex. The optics should be a true "macro" lens focusing to half life-size for multiple nails and, with an accessory tube, to life-size (X 1 or 1:1) for individual nails. If a choice of focal length macro lenses is available, the longer-length lens is preferable, somewhere between 90 and 120 mm, depending on the manufacturer. A portable electronic flash unit with both thyristor circuitry plus macro focusing sensor calibration is recommended. A flash bracket enabling off-camera flash positioning will provide shadow-producing "pointlight" illumination for delineating pictorial texture and anatomic architecture. One film should be standardized: a daylight-rated color film producing slides not prints, preferably Kodachrome 64 or Ektachrome 64 or 100, manufactured by Eastman Kodak Co. The ASA rating of the film should be matched with the power of the flash unit so that exposure should be a minimum of f.11 or f.16 to provide adequate depth of field at the close-up and ultra close-up magnifications required for nail pathologies. Patient and camera should be positioned so that the major axis of the anatomic site parallels that of camera back (plane of film). The image should fill up as much of the film frame as possible by moving the camera system into close-ups while retaining anatomic landmarks and some portion of uninvolved nail or skin in the immediate area. Film inventories should be stored in either a refrigerator or freezer to avoid heat- and humidity-induced degradation of imaging. When exposed, the film should always be developed by the same processing laboratory, preferably one of Eastman Kodak's regional laboratories throughout the United States.