Ilford SFX 200

Research-backed original, derived from the Ilford SFX 200 datasheet (archived, Nov 2018). A medium-speed B&W with extended red sensitivity up to 740 nm, not true infrared, but far enough past the visible band to produce near-black skies and an unusual, slightly unearthly tonal architecture. Derivation, and a honest account of the one thing this recipe cannot do, in the notes.

Read this before shooting it: what this recipe can and cannot reproduce

Ilford describes two effects when SFX is used with a deep red filter:

"by using a very deep red filter, skies can be rendered almost black, and most green vegetation almost white."

This recipe delivers the first and cannot deliver the second. It will render foliage dark, which is the opposite direction.

The reason is physical, not a tuning failure. SFX's pale-foliage effect comes from the vegetation red edge: chlorophyll absorbs strongly through the visible red and then becomes nearly transparent above about 700 nm, so leaf reflectance climbs steeply, by a factor of five or more. Across roughly 680-750 nm. SFX's sensitivity reaching 740 nm catches the bottom of that ramp. The X-T5, like every unconverted digital camera, sits behind a IR-cut (hot mirror) filter whose transmission falls away through the 600s. That band is simply not recorded. Meanwhile ACROS+R works on the visible red channel, and Fujifilm's own manual describes the colour filters as deepening "shades of gray corresponding to hues complementary to the selected color", a red filter darkens greens. In visible light healthy foliage reflects little red, so it goes dark.

So: skies, architecture, townscapes, portraits and the general strangeness. Yes. White trees, no. For that you need a converted body or the actual film. The full argument, with sources, is in the notes. This supersedes the master list's older shorthand that "Acros+R approximates" SFX. It approximates half of it, precisely.

Why these values

• ACROS+R. The datasheet's whole premise is "especially suited for use with a red filter", and the manual's description of ACROS+R, "Enhances contrast and darkens skies considerably" Is the closest thing the camera has to that. Plain ACROS is the fallback: the sheet notes SFX "also has full panchromatic sensitivity to make sure good pictorial contrast with or without the use of a filter," so the unfiltered variant below is faithful too, not a compromise.
• Highlight +1 / Shadow +1. Firm, but nothing like the reference recipe. The bank's attributed Acros Red High Contrast runs Highlight +3 / Shadow +4. That is a creative look and a good one, but it is not SFX. Ilford's sheet twice describes SFX as having a "wide tonal range" and "wide exposure latitude": its drama comes from spectral selection, not from a crushed curve. Let the +R filter do the work and keep the scale long. +1/+1 firms the mid-scale to match a red-filtered rendering without throwing away the range the datasheet claims.
• DR200. Slightly narrower than the 400-speed originals, matching the film's ISO 200 rating and the fact that red-filtered work is already a contrast-seeking exercise. Sets the ISO floor at 250, which sits right on the film's box speed.
• Sharpness 0, and there is a datasheet reason for it rather than mere restraint. The sheet makes no sharpness or acutance claim at all (compare XP2 Super, which puts "SHARP" in its product title). It does the opposite: it warns that "with some lenses, red light focuses at a slightly different point to other visible light," and recommends "stopping down to the smallest working aperture" to absorb the shift. Real SFX-with-red-filter frames are frequently a touch soft by construction. Sharpness 0 is faithful to that.
• Grain Weak, Small, the weakest-evidenced value here, stated as such. Ilford publishes no granularity figure for SFX. This places it by speed class: a 200-speed conventional emulsion between Delta 100 (Weak/Small) and the 400s (Strong/Small). If a real scan turns up reading grainier, this is the first setting to move, see the reference set.
• ISO 250-800. The sheet's own development-time tables run at exactly EI 200 / 400 / 800 and stop there. DR200 sets the floor at 250. The band is narrow on purpose: this is a bright-light film, and Ilford says so, "best results are obtained in bright sunshine, or in the studio under tungsten lighting."
• Exposure Compensation 0 to +1/3, and the digital version deletes SFX's biggest headache. Shooting the real film means stacking a filter factor (Ilford's table: Red 25 = 1½ stops, Deep Red 29 = 1⅔, Very Deep Red 89B = 4 stops) on top of a TTL meter that the sheet warns "can under expose by up to 1½ stops with deep red or orange filters in place", which is why Ilford tells you to bracket ±2 stops. On the X-T5 the "filter" is applied in processing, after metering. There is no filter factor and no metering error. Meter normally.
• Clarity 0, High ISO NR −4, Monochromatic Color 0: house defaults. No "edge contrast" language in this sheet, so Clarity stays at 0 on the same standard applied to Delta 100.

Variants

Handling

• Bright sun is the design condition. Ilford says it outright. Under flat overcast the red-filter effect largely disappears, there is no blue sky to darken, and you are left with a slightly odd panchromatic B&W.
• Meter normally. The whole filter-factor / bracket-±2-stops ritual that real SFX demands does not transfer. This is the rare case where the digital version is strictly easier than the film.
• Where it sits: this is the only original here on a red-filtered Acros base, and its distinctiveness is spectral rather than tonal. Three other originals use a filtered Acros, all of them tonal rather than spectral in intent: Ortho Plus and Silver Veil on green, Tri-X 400 on yellow. For high-contrast B&W drama by tone curve instead, see the reference Acros Red High Contrast. For grit, Tri-X 400.
• Video: Film Sim + DR (manual) + Tone Curve transfer. The +R filter is part of the film simulation and does carry into movie mode, unlike Grain and Clarity (see Video / Movie Mode, settings, differences, and photo→video translation).

Validation tier: Datasheet-validated, partial-fidelity, a tier of its own, and the honest label. Grounded in the archived Ilford SFX 200 technical information (Nov 2018): 740 nm extended red sensitivity, ISO 200/24°, the EI 200/400/800 development tables, the full filter-factor table, the stated red-filter effects, the focus-shift caution, the "bright sunshine or tungsten studio" design condition, and the wide-latitude / wide-tonal-range claims. Partial-fidelity because one documented effect of the film. Pale foliage. Is not reproducible on an unconverted digital body, for the spectral reasons set out above and in the notes. No real-film scan yet.

Highest-value scan for the reference set: a red-filtered SFX frame containing both a blue sky and green foliage. That single frame settles how far apart the film and this recipe really are, and would let the foliage caveat be quantified instead of argued.

Datasheet-derived original, tier: datasheet-validated, partial-fidelity. Primary source: Ilford SFX 200 technical information, Nov 2018. Archived locally at the datasheet archive, 6 pages, read in full. Settings in the notes.

What the datasheet says

Filter factors, from the sheet:

Note what the 89B row implies: at four stops of filter factor on a ISO 200 film, Ilford's own worked example is "1/30th second at f5.6" in bright sunlight, and it recommends a tripod. Real SFX at the dramatic end is a slow, deliberate process. The digital translation is not, which is worth knowing when judging whether a frame "looks like SFX."

The finding: what ACROS+R can and cannot reproduce

This is the substantive research result of this derivation, and it corrects a piece of shorthand the bank was already carrying, Film Stocks Master List, the Canon of Top Stocks & Recipe Coverage previously logged SFX 200 as " (Acros+R approximates)" That is half right, and the half it gets wrong is the more famous half.

The sky: reproducible

A blue sky is strongly blue-reflecting and weakly red-reflecting. Any red filter. Optical or computational. Suppresses it. Fujifilm's manual describes the ACROS colour filters as deepening "shades of gray corresponding to hues complementary to the selected color", and ACROS+R specifically as "Enhances contrast and darkens skies considerably." This lands in the same place as SFX-plus-red-filter. No caveat needed.

The foliage: not reproducible, and the recipe goes the opposite way

Ilford's second stated effect, "most green vegetation almost white" Is a near-infrared phenomenon, not a red-filter phenomenon.

1. The mechanism is the vegetation red edge. Chlorophyll absorbs strongly across the visible spectrum, including deep into the red, and then becomes almost transparent above roughly 700 nm. With nothing left to absorb the light, it scatters back out and leaf reflectance rises sharply, by a factor of five or more. Across approximately 680-750 nm. This is standard remote-sensing physics. It is the same effect that makes foliage glow white in true infrared photography (the Wood effect, named for Robert Wood).
2. SFX catches the bottom of that ramp. Deliberately, and only just. Ilford's 740 nm ceiling reaches into the rising edge but not far up it. This is exactly why SFX is described everywhere as producing an infrared look rather than true infrared, and why its foliage renders pale-grey rather than the luminous white of a genuine IR film. Ilford's own sheet is careful about this too, "unlike true infra-red film," it can be loaded in subdued light.
3. The X-T5 cannot record that band at all. Every unconverted digital camera has a IR-cut / hot-mirror filter bonded over the sensor, whose transmission falls away progressively through the 500-700 nm region and is effectively closed before the red edge starts. This is not a Fujifilm quirk: infrared-conversion services exist precisely to remove that filter, and offer the service for Fujifilm X-mount bodies.
4. So ACROS+R operates entirely on visible red, where foliage is dark. Chlorophyll's strongest absorption sits around 660 nm, right in the visible red. Healthy leaves reflect little red light. A red filter therefore darkens foliage, which is precisely what Fujifilm's manual says the filters do to complementary hues. The recipe fails to lighten the leaves and pushes them the other way.

What that means in practice

The only routes to the foliage effect are an infrared-converted body or shooting the actual film. There is no in-camera setting, no WB shift and no tone-curve move that recovers it, because the information was removed by a piece of glass in front of the sensor before any processing happened.

This is a clean, concrete instance of the bank's founding argument in Why Fujifilm Film Simulations Cannot Be Replicated in Post-Production, that a film simulation is a spectral-sensitivity-aware conversion of the raw sensor signal, and cannot recover what the sensor never received. Usually that argument is made about colour dye layers and is hard to show. Here it reduces to a single number: 740 nm, on one side of the hot mirror or the other.

Sourcing note

The Ilford figures above are primary and archived. The red-edge physics is well-established published science, cited here from general remote-sensing and infrared-photography literature (Wikipedia's Red edge. Standard treatments of the Wood effect) reached via web search. Full-text fetches of those pages returned HTTP 403, so they are recorded at search-snippet level rather than as verified full-page reads. The hot-mirror claim comes from infrared-conversion vendors' published descriptions of stock camera filters (Kolari, Life Pixel), also at snippet level. No manufacturer publishes the X-T5's exact IR-cut transmission curve, so the recipe and this page describe the cutoff qualitatively rather than quoting a number Fujifilm has not stated. Anyone wanting to harden this: a X-T5 frame of foliage through a physical R72 filter, at a long exposure, would settle empirically how much leaks through.

The tone-curve decision

The obvious move would be to copy the bank's attributed Acros Red High Contrast, which runs Highlight +3 / Shadow +4 on the same base. It is a good recipe. It is not this film.

Ilford describes SFX twice as having a wide tonal range and a wide exposure latitude, and calls its rendition "unusual" rather than "contrasty." SFX's drama is spectral. It comes from recording a band the eye does not see, then filtering it. Stacking a hard tone curve on top would be modelling the reference recipe's aesthetic rather than the film's data, and would flatten the very tonal range the sheet advertises.

So: Highlight +1 / Shadow +1. The +R filter supplies the separation. The curve stays long. The "maximum drama" variant exists for anyone who wants the 89B end, and it is labelled as a choice rather than as fidelity.

The Sharpness 0 decision

Unusual for this bank, and worth its own note. The sheet makes no acutance or sharpness claim whatsoever. Contrast that with XP2 Super, whose product title is literally "SHARP, FINE GRAIN." What SFX's sheet does instead is warn about a focus shift: red light comes to focus at a slightly different point than the rest of the visible spectrum, and Ilford's remedy is to stop down to the smallest working aperture, noting only apochromatic designs may need no correction.

That means a genuine SFX-plus-deep-red frame is frequently marginally soft by construction. Sharpness 0 records that. The architecture variant lifts it to +1, on the reasoning that the digital "filter" is applied after capture and therefore causes no focus shift, so on stone and glass the datasheet's own reason for restraint does not apply.

The weakest value in the recipe

Grain. Ilford publishes no granularity figure for SFX, no RMS, no grain index, nothing comparable to Acros 100's RMS 7 or the T-grain construction language in the Delta sheets. Weak, Small is placed purely by speed class: a 200-speed conventional emulsion, sitting between Delta 100 and the 400-speed originals. That is an interpolation, not evidence, and it is the first thing to change if a real scan says otherwise.

What the digital version fixes

Worth recording because it cuts the other way for once. Normally these derivations are a list of what is lost.

Shooting SFX for real means compounding two exposure problems: a filter factor of 1½ to 4 stops depending on how deep the red is, and a TTL meter that Ilford warns "can under expose by up to 1½ stops with deep red or orange filters in place." Hence the sheet's advice to bracket ±2 stops and to run a calibration roll before starting.

On the X-T5 the +R "filter" is part of the film simulation, applied to the signal after metering. The filter factor and the metering error both vanish. Meter normally, shoot at 0 to +1/3, keep the shutter speed you would otherwise have had, no tripod required for what Ilford calls a 1/30 at f5.6 in bright sun. That is a genuine, concrete advantage of the digital translation, and one of very few in this bank.

Validation status

Datasheet-validated, partial-fidelity. Every setting traces to the archived Ilford sheet. The partial-fidelity label is not hedging. It names a specific, physically-grounded, permanently-unreachable gap (foliage), while the rest of the film's documented behaviour is reproduced.

No real-film scan yet. The single most valuable frame for the reference set is a red-filtered SFX exposure containing both blue sky and green foliage, which would let the caveat above be measured rather than argued, and would also settle the grain question in the same frame.

Derived: 2026-07-25