film_grain — GFX2D post op

• Data kinds: rgb → rgb

• Call: import gfx2d; gfx2d.film_grain(rgb, sigma=0.03, seed=0, monochrome=True) (or opsgfx2d.get("film_grain"))

Usage

Add zero-mean Gaussian grain, deterministically from `seed`.

`monochrome` adds the same noise to all three channels (what film grain

does — the silver halide crystal is not coloured); set it false for sensor

read noise, which is per-channel.

`sigma=0 returns the input bit for bit. The clip at [0, 1]` biases the

mean wherever the image is already near an end of the range; the suite

measures the shift (2.4e-4 on a mid-grey image at sigma=0.03, 1.0e-4 on a

half-black half-white one) rather than claiming it is zero.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• gfx2d_scene — py -3.11 examples/gfx2d_scene.py

Ops the type connects to (they accept rgb as input)

srgb_to_linear · linear_to_srgb · blend_mode · light_mask · normal_map_decode · bloom · vignette · chromatic_aberration

Same category (post)

bloom · vignette · chromatic_aberration · color_lut · color_grade · dither · palette_quantize

*Provenance: gfx2d.py — GFX2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.