Kodak Tri-X Reversal 7278

Tri-X Reversal 7278 is the black and white motion picture film that defined television news and student documentary work for half a century. Kodak introduced it in 1955 as the 16mm and Super 8 sibling to still Tri-X, with a separate sensitometric profile suited to reversal processing rather than negative work. Kodak kept the Super 8 cassette in production alongside the 16mm rolls until the 2003 changeover. The 16mm 7278 designation lasted until 2003, when Kodak rebranded the current emulsion as 7266 on Estar base.

The film rates 200 ASA in daylight and 160 ASA under tungsten. Reversal means the camera negative becomes a positive after processing, ready to project directly without a print step. That economy is why every news bureau and student film program in the sixties and seventies ran on 7278: one trip through the lab and you had a screenable copy. The lab used D-94A first developer with R-10 bleach, a process essentially gone now outside specialty houses like Cinelab and Pro8mm.

The look is sharper than negative Tri-X. Reversal stocks have shorter tonal scales and steeper curves than negative film, so contrast runs high and highlights compress fast. Shadows block earlier too. News rushes carried a punch and a willingness to drop into pure black, both of which read as journalistic immediacy on a CBS or BBC broadcast.

Cross-processing as negative in D-76 was a known trick. You lost a stop of speed and gained grain, but the result was usable if you ignored the antihalation undercoat.

Formats were 16mm, Super 8, and Double Super 8 only. There was never a still 35mm or 120 version. Anyone shooting 7278 short ends today is running them through a Bolex H16 or a Beaulieu 4008.

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. In practice this rarely matters: motion picture cameras run at 24 or 18 frames per second, and the shutter time per frame is a fraction of a second. The math is for the rare still-camera use of leftover short ends.