Kodak Ektachrome 100 Professional

Ektachrome 100 Professional, code EPN, arrived in 1984 as Kodak's neutral-palette professional slide film. Where Velvia and Kodak's own Ektachrome 64 leaned saturated, EPN was tuned for accurate color reproduction. Catalog photographers, fine-art reproduction shooters, and museum documentation crews used it for that reason. If you needed a slide that would survive being matched against a real-world reference under D50 lighting, EPN was the choice.

The grain was extremely fine for an ISO 100 chrome, and the D-min was low. That is the technical way of saying the unexposed base was very clean and the whites read as whites rather than faintly tinted off-whites. Compared to Provia 100F, EPN ran cooler with less saturation, and compared to its own descendant E100G (introduced 2003 to replace the older E100S and E100SW emulsions), the contrast curve was a touch shorter with a slightly less graceful highlight rolloff. The film never had Velvia's landscape look, and was not trying to.

E-6 processing is standard. Latitude is the usual slide knife edge: half a stop over and the highlights are gone, a third under and the shadows block. Bracketing was routine. Pull-processing one stop was clean. Pushing past one stop brought visible grain and a slight cyan shift in the shadows.

Kodak ended EPN production in December 2007, citing low demand and the complexity of the formulation. The rest of the Ektachrome line followed in 2009, 2011 and 2012. The Ektachrome line as a whole was discontinued in 2012, with E100 returning in 2018 on E100G architecture, not EPN. Cold-stored freezer rolls hold up. Warm-stored ones develop a magenta cast no scanner profile can fully unwind.

EPN was sold in 35mm, 120, and sheet sizes through 8x10. Catalog studios used the 4x5 and 8x10 sheets.

Reciprocity exponent is 1.1, which is mild. Zone Light Meter applies the correction past one second. A metered 4-second exposure becomes roughly 5 seconds at the slide, a small enough adjustment that bracketing usually covers it before the math does. For longer tripod work on architecture or copywork, the correction stays modest but real.