KodakTri-X 400

Kodak Tri-X 400 is a high-speed panchromatic black-and-white negative film, developed in standard black-and-white chemistry such as D-76, HC-110 or XTOL [1]. It has been sold since around 1940 and was re-engineered in 2007 under the code 400TX [6]. It kept its name when Eastman Kodak took over its distribution in January 2026 [4] [5].

Look and color

Tri-X turns colors into grays according to its own spectral sensitivity, not the eye’s:

• Blue renders light. The film is more sensitive to violet and blue than the eye [1], so blue skies come out pale without a filter. Analogue Wonderland also notes that blues render “the lightest” [8].
• Skin and reds render a little darker. Converting our test RAW files with the Tri-X curve instead of plain luminance made a sky 3.2 L* lighter, skin 3.8 L* darker and a pink shirt 1.2 L* darker [13].
• Filters. To darken skies, Kodak gives daylight filter factors of 2 for a No. 8 yellow, 2.5 for a No. 15 deep yellow and 8 for a No. 25 red [1].
• Reviews describe “bold contrast, rich tones” [9], “deep, obsidian blacks and crisp contrast” [8] and a “ready-to-publish contrast” that needs little editing [7].

Tonality

• Curve. On the datasheet’s characteristic curves, base plus fog sits near 0.3 density. The toe is long and gradual (about one log unit), the straight section long, and there is almost no shoulder: highlights keep separating (our reading of the graph) [1].
• Development sets the contrast. Kodak’s starting-point times target a contrast index of 0.56, and the datasheet plots contrast index against development time for seven developers [1]. The same film can look flatter or harder depending on the developer and time.
• Compared with other 400s. In one side-by-side test, Tri-X rendered a gray backdrop darker with a wider tonal range, while HP5 Plus and T-Max 400 came out flatter [10].
• Latitude. Kodak lists “wide exposure latitude” [1]:
  • one stop of underexposure with normal development gives a slight loss of shadow detail;
  • two stops (EI 1600) or three stops (EI 3200) need push development, with more contrast and grain and less shadow detail.
• Long exposures: no correction from 1/100 to 1/10 s. From 1 s, add 1 to 3 stops and shorten development by 10 to 30 % [1].

Grain and sharpness

• Kodak calls an RMS of 17 “fine” [1]. RMS values measured in different developers are only roughly comparable.
• Reviews: “relatively fine-grained for ISO 400”, with grain showing when zooming into 35 mm scans [7]; “distinctive grain” [9]; grain becomes “pronounced” when pushed [8].
• Sharpness: Kodak lists “high sharpness” and “high resolving power” but gives no lines-per-millimeter figure, only a modulation transfer curve [1].

Spectral sensitivity

On an equal-energy basis, sensitivity is highest in the violet and blue (around 360 to 400 nm), dips near 505 nm, rises again to a broad maximum around 575 nm with a small peak near 620 nm, then falls steeply past 625 nm to the bottom of the chart near 668 nm [1]. In practice, blue skies turn lighter and skin and reds darker than in a luminance conversion [13]. Kodak’s 2007 edition notes that this curve was measured on the older Tri-X Pan 5063 emulsion and is expected to apply to the new one [2].

Names, status and history

• 1940 and 1954. Tri-X was introduced around 1940 in sheets, rated ASA 200 in daylight and 160 in tungsten, and released in 35 mm and 120 in 1954 [6] [7].
• 2007: 400TX. Kodak moved black-and-white production to a new coating facility and warned of slightly different processing times [2]. The film was re-engineered, took the code 400TX instead of TX or TX400, became finer-grained and uses less silver [6].
• Tri-X 320 is a different film. The 2021 datasheet lists Tri-X 320 (320TXP) in sheets only, with its own curves and an RMS of 16 [1].
• 2026: Eastman Kodak. Since January 2026, Eastman Kodak distributes Tri-X 400 directly, in new packaging, instead of Kodak Alaris [4]. Unlike Portra and T-Max, it kept its name [5]. On September 29, 2026, Kodak’s site listed 135-24, 135-36, 35 mm × 100 ft and 120 [3]. The datasheet also mentions a Tri-X 400 single-use camera [1].
• Datasheet. The most recent datasheet we found is F-4017 from October 2021, published by Kodak Alaris [1].