Kodak Aerial Double-X 2405

Aerial Double-X 2405 is the aerial mapping cousin of the still and motion picture Double-X line. Kodak coats it on 3.9-mil ESTAR polyester base for dimensional stability across the temperature swings of unpressurized survey aircraft, where a film that stretches a thousandth of an inch ruins the geometry of a stereo pair. Total thickness is 4.50 mils, with 0.40 mil of emulsion and a dyed-gel anti-halation backing. The base is why 2405 exists as a separate product; the panchromatic emulsion is closely related to 5222 and 7222.

The film carries extended red sensitivity that lets yellow and orange filters cut atmospheric haze. Spectral response runs flat through the visible range and into the deep red. Without filters, a frame from 20,000 feet shows washed-out terrain from Rayleigh scattering. A Wratten 25 or 29 restores contrast to where ground features become readable.

Aerial film speeds use the EAFS system, not ASA, but most users settle around EI 200 in D-76 or Xtol. Some bulk-load 2405 into 35mm; some cut it to 4x5 sheet. Photrio threads carry accounts of the film hand-rolled into cassettes after surplus 70mm or 9.5-inch rolls land at auction. Grain is medium, contrast moderate, both intentional for mapping where mid-tone discrimination matters more than punch.

Compared with 5222 cut down for still use, 2405 is more dimensionally stable but harder to load because rolls come unperforated. Against FP4+ or T-MAX 100 the aerial stock has straighter mid-tones and less highlight separation. A technical film. That is the point.

Kodak still produces 2405 for the surviving aerial market. It sells in widths from 70mm through 9.5 inches, no 35mm or 120 retail. Stills users source through surplus or eBay sellers who picked up film at auction.

The reciprocity exponent is 1.31. Zone Light Meter applies the correction past one second. A metered 30-second exposure becomes about 90 seconds at the negative. Aerial work rarely runs past 1/500, so the math is for ground use, where it lines up with the cubic-grain silver family.