Ansco Plenachrome

Plenachrome was Ansco's box-camera film, and it predates almost everything else still discussed on photography forums. The Binghamton, New York factory turned it out from the early 1930s through the early 1950s, when the post-war shift to panchromatic emulsions pushed it off the shelves. Super Plenachrome ran alongside it as a slightly faster sibling, both marketed as snapshot film for the millions of Ansco Speedex and Plenax rollfilm cameras in American homes.

The emulsion is orthochromatic, which is the defining technical fact. Plenachrome is blind to red. Skin tones come back darker than the eye expects, lipstick reads almost black, and a red barn at sunset becomes a silhouette against a properly exposed sky. Blues and greens render lighter than panchromatic stocks render them. Grain is large by modern standards and resolution is modest.

In 1952 Ansco published Plenachrome at 50 daylight and 25 tungsten under the old ASA system. When the safety factor was removed from ASA in the 1960s the effective speed doubled, putting modern-equivalent sensitivity closer to 100 in daylight. Most surviving stock rates around 25 to 50 today after sixty-plus years of base fog accumulation.

Plenachrome competed directly with Kodak Verichrome (the pre-Pan version), also orthochromatic and aimed at the same box-camera amateurs. Both films were rendered obsolete when Kodak introduced Verichrome Pan in 1956 and the consumer market shifted to panchromatic almost overnight. Ansco discontinued Plenachrome by the mid-1950s.

Formats included 116, 120, 127, 620, and 828 rollfilm. No 35mm version was made. Develop in HC-110 dilution H or Rodinal 1:50 for compensating tonality on the fogged base.

The reciprocity exponent is 1.31. Zone Light Meter applies the correction past one second. A 30-second meter reading climbs to about 90 seconds at the negative, and a five-minute exposure stretches well past fifteen. For long indoor tripod work, which is essentially the only sensible way to shoot this film today, the correction is routine.