Free Studio Lighting Contrast Ratio Key to Fill Calculator

Professional-grade utility for calculating studio lighting ratios. Ensure consistent exposure for your portraits and cinematography.

Input Parameters

Quick Presets

Contrast Ratio

2.0:1
Moderate Contrast
Flat Dramatic

Understanding Ratios

The contrast ratio is defined as (Key + Fill) : Fill. It measures the intensity difference between the brightest part of the subject and the shadows.

1:1 - 2:1

Low contrast. Ideal for beauty, commercial, or sitcom lighting. Very soft shadow definition.

3:1 - 4:1

Standard portraiture. Adds depth and modeling to the face while keeping shadows legible.

8:1+

Dramatic, high contrast. Used for mystery, suspense, or "Film Noir" styles. Deep, crushed blacks.

Note

If Key light is lower than Fill, ratio is undefined/negative. Ensure Key is the primary source.