About

Digital sensors capture light with clinical precision, often resulting in images that feel sterile or plastic. In analog photography, film grain is the optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons.

This tool is not a simple overlay. It generates algorithmic noise using Box-Muller transformation to simulate the natural Gaussian distribution found in physical film stocks. By manipulating the density, chroma, and scale of the grain, you can emulate specific film speeds ranging from fine-grain ISO 100 to gritty ISO 3200.

We use advanced composite blending (Overlay/Soft Light) to ensure the texture respects the luminosity of your image - preserving deep blacks and bright highlights while adding texture to the mid-tones.

Formulas

The generator uses a Gaussian distribution for naturalism, contrasting with the uniform distribution of standard digital noise.

{

u = 1 - random()v = random()z = √-2ln(u) ⋅ cos(2πv)

The pixel value P_final is calculated using the Overlay blend mode logic:

{

2P_baseP_grain if P_base < 0.51 - 2(1-P_base)(1-P_grain) otherwise

Reference Data

Film Stock Simulation	ISO Rating	Grain Structure	Recommended Settings
Fine Art 100	100	Micro-contrast, barely visible	Size: 0.8, Opacity: 15%, Mono: TRUE
Studio Portrait 400	400	Standard pleasing texture	Size: 1.2, Opacity: 30%, Mono: TRUE
Street Cinema 800T	800	Noticeable, moody	Size: 1.8, Opacity: 45%, Mono: FALSE
Gritty Documentary	1600+	Heavy, abstracting detail	Size: 2.5, Opacity: 70%, Mono: TRUE
Digital Sensor Noise	N/A	Uniform RGB pattern	Size: 1.0, Opacity: 25%, Mono: FALSE, Blend: Screen

Frequently Asked Questions

To ensure 60fps performance while you adjust sliders, the preview renders on a downscaled version of your image. The download button re-processes your full-resolution original file with the exact same mathematical seed.

For authentic film simulation, use Monochromatic. Physical film grain is texture, not color error. Use Color noise only if you want to simulate high-ISO digital sensor artifacts or a specific lo-fi digital aesthetic.

Unlike a simple opacity layer which washes out blacks, Harmony Blending uses "Overlay" or "Soft Light" math. This ensures that pure blacks and pure whites remain largely untouched, while the grain is applied primarily to the mid-tones, mimicking how film emulsion density works.

If you are exporting for Instagram or Web (1080px width), a larger grain size (1.5 - 2.0) is often necessary to be visible after compression. For 4K printing, a finer grain (0.8 - 1.0) is preferred.