Kodak Plus-X Negative 7231

Plus-X Negative was the slower companion to Double-X in Kodak's motion picture catalog. The 7231 designation referred to the 16mm version; 5231 was the 35mm equivalent. Both ran on the same emulsion. Kodak introduced the modern Plus-X Pan in 1938, revised the cinema variant in 1956, then kept it on the price list for fifty-four more years before discontinuing it in 2010.

Nominal speed is 80 in daylight, 64 under tungsten. The grain is fine, sharper and tighter than Double-X but not at the level of T-MAX 100 or Delta 100, and the tonal scale is longer and gentler than 7222. Cinematographers reached for Plus-X when a scene needed fine detail and forgiving mid-tones rather than the harder contrast of Double-X. Janusz Kaminski used 5231 for the brighter scenes in Schindler's List, holding 5222 for high-contrast night and interior work.

The character is closer to old-school Plus-X Pan still film than to anything currently in production. Picture FP4+ with a touch more contrast and a less modern grain. Latitude is moderate. A stop of overexposure looks fine; two stops over and the highlights pile up. A stop under and the shadows hold; further than that and you lose detail you cannot get back.

Like all Kodak motion picture stocks, 7231 carried a remjet backing that has to be removed before standard still-photography development. Discontinuation in 2010 means there is no fresh stock anywhere. What turns up on eBay is at least fifteen years old. Expect base fog. Rate it at 50 or 40 to compensate. D-76 at 1:1 still works well even on rolls that have sat in someone's garage since the Bush administration.

Reciprocity exponent is 1.31. Zone Light Meter applies the correction past one second. A 75-second meter reading runs to about 90 seconds at the negative. At ISO 80 you cross the one-second threshold faster than with Double-X or HP5+, so the correction enters the working range often. Plan for it on indoor architectural and tabletop work in particular.