Ilford Delta 100

Research-backed original, derived from the Ilford Delta 100 Professional datasheet (archived). Reproduces Ilford's medium-speed T-grain (tabular grain) precision stock: ISO 100, fine grain, built for pictorial and fine-art work, the modern-emulsion sibling to Acros 100 at the same box speed. Derivation in the notes.

Why these values (short)

• Acros base: the premium B&W profile. The right canvas for a stock Ilford itself pitches for "pictorial and fine art photography."
• Grain Weak, Small: datasheet: "medium speed, fine grain." Delta 100 is built on Ilford's core-shell tabular (T-grain) technology, the same crystal family as Delta 3200. T-grain crystals present a flatter, more regular boundary to light than the older cubic-grain emulsions, which is the physical reason tabular-grain films read smoother rather than "sparkly" at a given speed. Same fine tier as Acros 100 and Pan F Plus 50.
• DR200, Highlight 0, Shadow +1: the datasheet gives development-time tables but, notably, no stated contrast index or "edge contrast" claim for this stock (unlike Pan F Plus 50's sheet, which explicitly calls out edge contrast, see below). With no documented reason to push contrast harder, this recipe sits close to neutral rather than borrowing Pan F's firmer curve.
• Sharpness +1: a modest lift appropriate to a precision fine-grain stock, without asserting an "edge contrast" claim the datasheet doesn't make.
• Clarity 0, a deliberate, evidence-based difference from Pan F Plus 50. Both are Ilford "fine grain, precision" B&W stocks marketed in similar language, but only Pan F Plus 50's own datasheet uses the phrase "edge contrast" as a named characteristic, which is exactly what Clarity models, and is why that recipe runs Clarity +2. Delta 100's sheet makes no such claim, so the bank's Clarity-0 default holds here. Same standard, applied consistently, different result, because the underlying evidence is different.
• ISO capped at 1600: the datasheet's own recommended exposure index range is EI 50-200 ("best results at EI 100... Good image quality from EI 50/18 to EI 200/24"), the narrowest latitude of any B&W original except Pan F Plus 50. The digital ceiling sits between Pan F's 400 (the bank's slowest, most protected stock) and Acros's 3200 (the established high-versatility workhorse), which puts Delta 100's headroom where the datasheet puts it: real, but modest.
• Reciprocity note, for context: the datasheet states no adjustment is needed between 1 second and 1/10,000 second, a genuinely wide reciprocity-free window for a conventional film, useful to know if you're chasing the chemistry rather than just the digital recipe.

Handling

• Controlled or good outdoor light, pictorial and fine-art subjects: architecture, landscape detail, still life. This is not a low-light film. Treat it like Pan F Plus 50, just with a stop more real-world speed and latitude.
• For a softer, more classic-grain alternative at the same box speed, use Fujifilm Acros 100, the two sit side by side as "T-grain precision" vs "Fujifilm's own reference B&W."

Validation tier: Datasheet-validated (EI range, T-grain construction, reciprocity data, pictorial/fine-art positioning, archived PDF). Characteristic pass: consistent with widely-documented T-grain-vs-cubic-grain behaviour. No real-film scan yet. This recipe has not been checked against an authentic Delta 100 frame.

Pro tip: Why this is not "Acros 100 with a different name" (2026-07-25). Same box speed, same "fine grain for serious work" pitch, but the underlying crystal technology differs (T-grain vs Fujifilm's own Acros grain model), and only one of the two documented B&W "precision" stocks in this bank (Pan F Plus 50) carries an explicit edge-contrast claim. The lesson generalises: read what a datasheet does and doesn't say before porting settings between similar-sounding stocks, see Film Chemistry Fundamentals. Why Film Looks the Way It Does on why grain size, crystal shape and contrast are chemically coupled rather than merely labelled.

Original (datasheet-validated). See the notes, the B&W README, and the Knowledge base.

The film

Ilford Delta 100 Professional, a medium-speed, fine-grain B&W film built on core-shell tabular (T-grain) crystal technology, the same emulsion family as Delta 3200 but at the opposite end of the speed range. The datasheet (archived, Apr 2023) states a speed rating of ISO 100/21°, with "good image quality" across EI 50/18 to EI 200/24, a genuinely narrow window compared to the bank's more forgiving stocks, and the datasheet is explicit that this range is "based on a practical evaluation of film speed... Not based on foot speed, as is the ISO standard." Ilford positions it plainly: "ideal for pictorial and fine art photography."

Why this was a gap worth closing

Film Stocks Master List, the Canon of Top Stocks & Recipe Coverage had flagged Delta 100 as a derivation candidate for some time, with a note that its datasheet was "already archived". Meaning the primary source had been sitting in this collection, unused, since the 2026-07-15 datasheet fetch. This recipe closes that gap using exactly the data that was already here.

T-grain vs conventional grain: the real distinction from Acros 100

Delta 100 and Fujifilm Acros 100 share a box speed (ISO 100) and near-identical marketing language ("fine grain," "rich detail"). What's actually different is the crystal geometry. Tabular (T-grain) crystals are flat and regular rather than the irregular cubic crystals of conventional emulsions. A flatter crystal boundary scatters light more predictably, which is the physical basis for T-grain film's reputation of looking smoother rather than "sparkly" at a matched speed, the same structural family Ilford uses at the opposite (3200) end of the Delta range. See Film Chemistry Fundamentals. Why Film Looks the Way It Does for why grain size, crystal shape and development chemistry are chemically coupled, not independent style choices.

The Clarity decision: the same standard, honestly applied to different evidence

This bank's rule is Clarity 0 by default, deviating only when the datasheet specifically justifies grit (Tri-X 400's "+3", Pan F Plus 50's "+2" for its own sheet's explicit "edge contrast" language). Delta 100's datasheet does not use that language. So despite Delta 100 and Pan F Plus 50 both being pitched by Ilford as fine-grain precision stocks, only one of them gets a Clarity boost, because only one of them's own paperwork asks for it. That is the validation methodology working as intended: read what the source actually says, not what a similar-sounding stock's recipe already did.

The grade in one line

The quietest, most restrained member of the B&W family, a precision, controlled-light stock positioned between Pan F Plus 50's extreme slow-speed "etched" character and Acros 100's do-anything workhorse versatility, without borrowing either one's specific personality.

vs the rest of the B&W family

Validation status

Datasheet-validated (ISO/EI table, T-grain construction, reciprocity data, pictorial-photography positioning, archived PDF). No real-film scan obtained yet, the honest state is datasheet-only, one tier below the bank's top standard.