Kodak Ektar 100

Original (research + curve-measured + scan validated). See the notes, the notes, and the Knowledge base.

The film

Kodak Professional Ektar 100, "the world's finest grain color negative film" per Kodak's own datasheet (pub. E-4046, archived in _reference-sources/datasheets/). ISO 100, daylight-balanced, KODAK Advanced Cubic Emulsions. Marketed for commercial/landscape photographers who want vivid, sharp, "digital-like" colour from film. Sheet specifics:

• Print Grain Index < 25 at 4×6 (25 = visual threshold). Essentially invisible grain at normal viewing size. 38 at 8×10, 66 at 16×20.
• "High saturation and ultra-vivid color."
• "Optimized sharpness" via the Advanced Cubic emulsion structure.

Real-scan confirmation (2 images, analysis-only)

1. Autumn street scene, daylight (a red vintage Porsche among golden foliage): saturated warm hues pop hard (red car, orange/gold leaves), asphalt and sky read close to neutral grey-blue (not warm-cast like Gold, not cool-cast like Superia), crisp detail throughout, no visible grain.
2. Night long exposure (railway station forecourt): deep near-black sky, warm tungsten building glow, vivid red tail-light streaks, brick texture still crisp. Fine grain holds up even under demanding low light, and the film shows real contrast capability (deep blacks + bright warm highlights) without crushing detail.

Both confirm the datasheet: saturated but neutrally balanced colour, very fine grain, and real sharpness. Neither is evidence about contrast relative to Portra, since neither is a matched pair, and the curve measurement in the notes says that comparison goes the other way from what this file used to claim.

The grade in one line

The most saturated, sharp, fine-grained colour negative in the bank. Slide-film colour delivered on a soft negative's tone scale, with no warm or cool cast of its own.

The correction that reshaped this recipe

This file used to say Ektar had "more contrast/punch than a forgiving portrait negative like Portra", and the recipe's … and Highlight … were set from that. Tracing Kodak's own characteristic curves puts Ektar at gamma 0.56 and Portra 400 at 0.58, a ratio of 0.96 to 1.02 across matched fit windows. The two films have the same contrast.

What Ektar actually has is saturation, and the sheet names the mechanism: "ultra-vivid color" comes from "Optimized Emulsion Spectral Sensitivity and Image Modifier Chemistry", which is a spectral property rather than a tonal one. So the vividness belongs in Color and Color Chrome Effect, and the tone curve should be set like the soft negative the film measures as. Highlight moved to … and Shadow to … as a result. Method, numbers and limits in the notes.

Why Velvia (tamed), not Classic Chrome or Classic Negative

• Classic Chrome is muted and desaturated, the opposite direction from Ektar's headline trait.
• Classic Negative shifts hues toward cyan/amber (the Superia signature), not what real Ektar does. Ektar's saturation boost is fairly even-handed across hues, not a stylised colour shift.
• Velvia is the only base vivid enough to match "ultra-vivid", so it is used here tamed at both ends: Highlight … and Shadow … give a negative's roll-off instead of a slide's, while keeping the saturation. The taming is heavier than it used to be because the film measures softer than this file used to assume.

Why it is not a portrait recipe, and why that is the recipe's fault rather than the film's

Color … on a saturated base pushes skin ruddy, which matches Ektar's real-world reputation as a landscape and product film. The datasheet does not agree with that reputation: Ektar publishes complexion-density targets identical to Portra 400's, at the same tight professional tolerance, and Kodak lists fashion photography among its recommended uses. So the emulsion is fine with skin and this recipe's saturation is not. Drop Color to … with Color Chrome Effect … for people.

vs the rest of the bank

• Kodak Gold 200: warm, soft, forgiving. Ektar is neutrally balanced, far more saturated, and less forgiving of exposure error. Both print to the same paper channel, so they cut together better than their looks suggest.
• Kodak Portra 400: muted saturation, skin-first, and measured at the same contrast as Ektar. The two films differ in colour, not in tone. Whether Ektar's latitude is genuinely tighter is an open question the datasheets cannot settle.
• BewareMyVelvia (Bold): a creative slide-film vivid look. Ektar is the negative-film vivid look. Same saturation ambition, different tonal handling (softer shoulder, less aggressive shadow).

Validation status

Datasheet-validated (PGI, complexion densities, reciprocity, filter tables, archived PDF), curve measured (gamma 0.56, traced from Kodak's published curves), and 2 real scans (daylight and night). Scan coverage across more light conditions is still pending: overcast, portrait skin, and any frame with a grey card in shot. Full evidence and limits in the notes. Drop images into references/.

Evidence base for the notes. Primary source is the archived Kodak sheet. The curve work follows the method and the warnings in Measuring film curves from datasheets — method, calibration, and its limits. Reference images analysed only, not redistributed.

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1. The headline result: Ektar is not a higher-contrast film than Portra

This recipe used to be justified by the claim that Ektar is punchier than Portra, with the tone curve set accordingly. That claim is now measured, and it does not hold.

Both curves were traced from the archived sheets with the same tracer, at 400 dpi, using the sliding-window estimator. Gamma is the mean of the three layer slopes.

Ratio over matched windows: 0.976, 0.962, 1.017. Within the precision of this method the two films have the same contrast, and Ektar is fractionally the lower of the two.

Three things make this trustworthy:

• Fit residuals are 0.011 to 0.015 density units, so both curves are genuinely straight over the fitted range rather than being forced through a bend.
• Both values sit inside Kodak's own patent range of 0.45 to 0.7 for colour negative, and in the same family as this bank's Measuring film curves from datasheets — method, calibration, and its limits measured VISION3 gammas of 0.526 to 0.554.
• The known weakness of this tracer is a possible scale error of up to about 12 per cent that n = 5 calibration cannot exclude. A ratio between two films measured by the same tracer on the same day cancels a common scale error, so the ratio is the more reliable number here, not the absolutes.

What follows for the recipe: Ektar's punch is a colour property, not a tone property. The sheet says so directly, attributing "ultra-vivid color" to "Optimized Emulsion Spectral Sensitivity and Image Modifier Chemistry", which is a spectral mechanism. Nothing on the sheet attributes vividness to contrast. So the vividness belongs in Color and Color Chrome Effect, and the tone curve should be set like the soft negative this film measures as.

2. What was attempted and failed: the latitude comparison

Reviewers consistently say Ektar has less exposure latitude than Portra and is "a bit more contrasty than the Portra family". Since gamma says otherwise, the obvious next test is the length of the straight section rather than its slope. That measurement was attempted and is not reportable.

Straight-line span in stops, swept over the linearity tolerance:

The apparent gap closes as the tolerance loosens and has vanished by 0.08. At 0.03 the layer ordering on Portra 160 inverts, with blue reading shorter than red. That is tolerance dependence, not a property of the film, and it is the same class of failure as the Measuring film curves from datasheets — method, calibration, and its limits 2383 retraction.

There is a second, independent reason the comparison cannot be made: Portra 400's curves are still straight where Kodak stopped drawing them, at log H +0.60, so its sheet gives only a lower bound. Ektar's plot continues past the point where its red layer departs, so the two sheets do not even cover the same question.

Status: the latitude claim is neither confirmed nor refuted here. The published curves cannot settle it. What is refuted is the narrower claim that Ektar has a steeper curve.

3. An observation that is deliberately not a finding

The trace shows the blue layer running 15 to 20 per cent steeper than green and red, on both sheets, stable across all five sliding windows.

It is recorded here and used for nothing, because it fails this bank's standard for an inter-channel claim. That standard, set after the 2383 retraction, is that a difference between channels counts only if it survives a change of estimator rather than merely a change of window. The density-anchored estimator was run as the cross-check and returned incoherent values for green and red (0.014 to 0.276 against 0.53 from the sliding window), which means the cross-check is broken rather than disagreeing. A finding with no working second estimator is not established.

Two further reasons for caution. The pattern differs from the VISION3 result in this bank, where green sits close to blue and red is the low one. Here green and red are nearly identical and blue is the outlier. And Measuring film curves from datasheets — method, calibration, and its limits the method's own self-audit notes that the Double-X calibration validates tracing one curve, not comparing three differently coloured curves on one chart, which is exactly what this would need.

No recipe setting depends on it.

4. The datasheet, mined properly

Kodak Publication E-4046, February 2016, archived at kodak-still/ektar-100_e4046.pdf.

Technology and the mechanism behind each claim

The sheet pairs each technology with the benefit it buys, which turns three recipe settings from taste into derivation:

The DIR couplers matter beyond sharpness. Development-inhibitor-releasing couplers are the standard mechanism for edge effects, and they are the same family this bank has already flagged as a Measuring film curves from datasheets — method, calibration, and its limits candidate mechanism for interimage behaviour in Kodak negatives. "Distinct edges, fine detail" is an acutance claim, which is why Sharpness goes positive here while Portra 400 sits at −1.

The VISION lineage is worth noting for anyone shooting both: Ektar shares cinema-film technology with the Vision3 stocks behind this bank's cinema recipes, as Portra 400 does.

Print Grain Index, complete

25 is the stated visual threshold for perception of grain, and a change of four units is a just-noticeable difference to 90 per cent of observers. At normal viewing size in 35 mm the grain is below the threshold, which is what Grain …/… encodes.

Skin, and a reputation that the sheet does not support

The sheet publishes complexion density targets, and they are identical to Portra 400's:

Same values, same tight professional tolerance of 0.10 on each row, against the 0.30 and 0.40 that the consumer UltraMax sheet allows. Kodak also lists "fashion and product photography" among the recommended applications.

So "Ektar is bad for skin" is a reputation rather than a datasheet claim. What the reviews actually describe, reds rendering strongly and warm skin drifting ruddy, is what happens when a saturated base is driven at Color …. That is a property of this recipe, not of the emulsion, and it is why the recipe ships a lower-Color variant for people rather than declaring the film unsuitable.

Handling facts the recipe now uses

• Reciprocity: "No filter correction or exposure compensation is required for exposures from 1/10,000 second to 1 second." Ektar holds without correction across four decades of shutter speed, which is unusually wide and directly supports the night long-exposure reference frame analysed below.
• Sodium vapour is the film's worst light by a wide margin. The sheet's correction for high-pressure sodium is 50B + 70C and +2 2/3 stops, the largest in its table. Cool white fluorescent needs only 30B and +1 stop by comparison. Practical consequence: this is the wrong recipe for a sodium-lit street at night.
• Speed is 100 in daylight or electronic flash, dropping to 32 under photolamp and 25 under tungsten with the matching Wratten filter, so the native look is a daylight look.

5. Reference frames (2 images, analysis-only)

1. Autumn street scene in daylight, a red vintage car among golden foliage. Saturated warm hues pop hard, while asphalt and sky read close to neutral grey-blue: not warm-cast like Gold, not cool-cast like Superia. Crisp detail throughout, no visible grain.
2. Night long exposure, railway station forecourt. Deep near-black sky, warm tungsten glow, vivid red tail-light streaks, brick texture still crisp. Fine grain holds up under demanding low light, and the frame shows real contrast capability without crushing detail.

Frame 2 is now better supported than it was: the reciprocity specification above says a long exposure needs no correction, which is consistent with a clean result at that exposure time.

Both frames confirm saturated but neutrally balanced colour, very fine grain, and real sharpness. Neither frame is evidence about contrast relative to Portra, since neither is a matched pair.

6. Validation status

• Datasheet-validated E-4046 archived, with PGI, complexion densities, reciprocity, filter tables, and the technology-to-benefit table all mapped to settings.
• Curve measured gamma 0.56, traced from Kodak's own characteristic curves, stable across five fit windows, and compared against Portra 400 measured identically.
• Characteristic widely and consistently documented as Kodak's most saturated colour negative.
• Scan-validated 2 frames only (daylight, night). Still missing: overcast, portrait skin, and any frame with a grey card in shot.

Highest-value additions to references/, in order: a portrait frame on real Ektar, since the skin question is where reputation and datasheet disagree most. An overcast frame, since both current scans are high-contrast light. And any frame with a grey card, which would let the near-neutral white balance be checked rather than inferred.

7. Sources

• Kodak Publication E-4046, KODAK PROFESSIONAL EKTAR 100 Film, February 2016 (archived locally).
• Kodak Publication E-4050, KODAK PROFESSIONAL PORTRA 400 Film, January 2025 (archived locally), used as the contrast comparator.
• Kodak Publication E-4051, PORTRA 160, used in the latitude attempt.
• Measuring film curves from datasheets — method, calibration, and its limits for the tracing method, the estimator discipline, and the calibration limits that bound what is claimed above.
• Reviewer consensus on latitude and skin behaviour: The Darkroom, Tim Layton Fine Art, Max Kent, Photrio discussion on skin-tone EI.