Ilford · ISO 100 B&W negative

Ilford Delta 100

B&W negative ISO 100 In production tabular grain · fine grain · open shadows

Delta 100 is Ilford's answer to T-MAX 100, and the two films are close enough that many labs and photographers treat them as interchangeable. They are not quite. The grain structure on Delta 100 is tabular, like T-MAX, but the curve is shaped differently in the shadow and highlight regions. Shadows on Delta 100 are more open and the highlights hold longer before they clip. For landscape printing in particular, that distinction matters when a scene has simultaneous deep shadows and a bright sky.

Fine-art printers who work in the wet darkroom often prefer Delta 100 over T-MAX 100 specifically because the highlight shoulder gives more room to dodge. At ISO 100 in good light the grain is very fine; the tabular structure also scans cleanly with tight focus and good drum scan settings, which makes it a strong choice for digital output.

Development is flexible. Ilfotec DD-X produces slightly finer grain and more open midtones compared to ID-11 or D-76, and it is worth the cost if you shoot Delta 100 regularly. The film tolerates moderate pull development well, useful if you want to lower contrast for a flat-lit architectural interior or overcast day landscape.

Ilford stocks Delta 100 in 35mm, 120, and 4x5 sheet film. The 120 format is where the tabular grain really earns its keep: at 6x7 or 6x9 the negative has so much detail that 16 by 20 fiber prints look continuous-tone.

Reciprocity exponent is 1.26, same as FP4+. Long exposures correct mildly. A 30-second reading becomes about 75 seconds of actual exposure. Zone Light Meter applies the Delta 100 curve past one second without any manual calculation, which keeps long-exposure bracketing sessions from becoming arithmetic exercises.

How the app handles this stock

  • Box speed: ISO 100. Picker exposes pull/push chips so you can shoot it at any speed you want and the meter follows.
  • Reciprocity: Above one second the app raises metered time to the power of 1.26.
  • Expired film: if you load an old roll, set the expiry year and storage in the app and the ISO scales for you. B&W negative decay rates are baked in.

Frequently asked questions

What ISO is Ilford Delta 100?

Ilford Delta 100 is an ISO 100 b&w negative film from Ilford. You can rate it at box speed or push and pull it; set the speed you actually shot and the meter follows.

Is Ilford Delta 100 still in production?

Yes. Ilford Delta 100 is a current film you can still buy new.

Does Ilford Delta 100 suffer from reciprocity failure?

Yes, on exposures longer than about one second. Its reciprocity exponent is 1.26, so a metered 10 seconds becomes about 18 seconds. Zone Light Meter applies this automatically.

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