Kodak Ektachrome EPR 64

Ektachrome EPR 64 arrived in 1976 alongside Kodak's E-6 process, replacing the older E-3 and E-4 chemistries that had defined the Ektachrome line for two decades. The code stuck: EPR for Ektachrome Professional Reversal, Kodak catalog 5017. Daylight balanced at ISO 64, the film sat in the middle of the Ektachrome speed range and became the working slide for editorial, landscape, and architectural shooters who wanted finer grain than the faster 100 and 200 stocks gave.

The color signature is what professional users describe as cool and clean. Whites stay white where Kodachrome 64 warms them slightly. Skin tones read naturally without the magenta lean of consumer slide films. Blues are honest rather than punched. That made EPR popular with National Geographic photographers shooting in conditions where Kodachrome 64 was too slow or where E-6 turnaround mattered more than K-14 dye stability.

Latitude is tight, as with any slide film, but EPR is more forgiving than Velvia 50 by a wide margin. A third of a stop of overexposure and the highlights hold; a third under and the shadows still print. Photographers who carry both will tell you EPR is the film for portrait, fashion, and architectural work where the subject controls color. Velvia is the film for landscape where the photographer wants the world to look bigger than it is.

Format coverage was wide: 35mm, 120, 4x5, and 8x10 sheet. Kodak discontinued EPR 64 in 2007 as part of the broader Ektachrome wind-down, well before the 2018 E100 reintroduction. E100 is the closest modern equivalent and shares the cool signature, though it is a half stop slower at ISO 100 and uses a different emulsion technology.

Reciprocity exponent is 1.10. Zone Light Meter applies the correction past one second. A 30-second meter reading lands at about 35 seconds at the negative, which keeps long-exposure architectural work in the practical range. For studio strobe at 1/250 or daylight handheld at 1/125, reciprocity is a non-issue and the film just behaves.