How to Build Film Simulation Recipes Using Kodak and Ilford Datasheets

Most film simulation recipes floating around the internet are built by eye. Someone looks at a scan of a Kodak Portra negative, twiddles the knobs on their Fujifilm camera until it looks close, and calls it a day.

If you want to build a truly accurate emulation, you have to bypass the guesswork and go straight to the source: the manufacturer's original PDF datasheet. Kodak Alaris, Fujifilm, and Ilford publish exhaustive technical specs for their film stocks. Once you know how to read them, you can translate objective chemistry data directly into subjective camera settings.

Emulsion-Faithful vs. Artifact-Faithful

Before you pull a single number from a datasheet, you have to decide what you are actually trying to emulate. You have two choices:

1. Emulsion-Faithful: You want settings that perfectly match the lab datasheet specs. You are trying to emulate the look of a perfectly exposed, freshly developed frame straight out of a professional lab.
2. Artifact-Faithful: You want settings that emulate how the film actually looked in the real world. You are trying to emulate the degradation of a cheap drugstore print, an aged slide, or a faded magazine page.

This distinction matters. For example, the Kodak Portra 400 datasheet proudly declares it the "world's finest grain high-speed film." If you build an emulsion-faithful recipe, you have to set your Grain to …/…. However, if you are chasing the look of a nostalgic, dusty consumer scan you found on Pinterest, you need an artifact-faithful recipe, which means cranking that Grain to …/…. Both are valid. You just have to know which target you are aiming at.

Translating RMS Granularity to Grain Effect

Film manufacturers measure grain using Root Mean Square (RMS) granularity. It's an objective measurement of how chunky the silver clumps get. You can map these RMS values directly to the Fujifilm Grain Effect settings on your X-T5.

• RMS 7 (e.g., Fujifilm Acros 100): This is as fine as film gets. Map this to Weak / Small.
• RMS 8-10 (e.g., Provia 100F, Ektachrome E100, Kodachrome 64): Still incredibly fine, typical of professional transparency film. Map this to Weak / Small.
• Consumer 200-400 Speed (e.g., Kodak Gold, UltraMax): These films use coarser T-Grain structures. Map this to Strong / Small.
• RMS 16+ (e.g., Kodak T-Max P3200, Natura 1600): These are aggressive, pushed films where the grain dictates the aesthetic. Map this to Strong / Large.

Reading the Characteristic Curve (D-log E)

If you scroll down any Kodak datasheet, you will find a graph called a Characteristic Curve (or D-log E curve). It plots exposure against density. This curve tells you exactly how to set your camera's Highlight and Shadow Tone.

• High Contrast / Brilliant Highlights: If the datasheet curve increases steeply in the middle and highlights clip aggressively, you need a steep digital S-curve. Push your settings to something like Highlight …and Shadow ….
• Low Contrast / Soft Gradations: If the curve is gentle and slopes smoothly into the shadows, soften your digital tone curve. Drop your settings to Highlight …and Shadow ….
• Extended Highlight Latitude: Cinema stocks, like Kodak Vision3, are engineered to hold massive detail in the highlights before blowing out. You emulate this long, rolling shoulder by setting your camera to … (…) and dropping your Highlights to …or ….

Mapping Color Balance and ISO

Datasheets also spell out the intended color balance and push tolerance, which dictate your White Balance and ISO strategy.

• Color Temperature: If a datasheet targets Daylight (5500K), use Daylight WB. If it targets Tungsten (3200K), dial your camera to 3200K or use the Incandescent preset.
• Subtle Casts: Datasheets often describe the exact hue shifts of a film (e.g., Portra 800's legendary warmth). Handle this in the WB Shift Grid by pushing Red and pulling Blue.
• Push Tolerance: If Ilford's datasheet explicitly states that HP5+ (a 400-speed film) thrives when push-processed to ISO 3200, build your recipe to encourage that behavior. Instruct the user to ride their ISO dial up to 3200 to organically force the camera to generate the heavy grain and contrast native to a pushed negative.