Gamma: the steepness of the tone curve that maps input exposure to output brightness; controls contrast in midtones.
Gamma is a measure of the steepness of the tone curve, i.e., the characteristic curve that describes the relationship between incident light (exposure) and the resulting image brightness. The term originally comes from sensitometry, where it described the characteristic curve of photographic film: it indicates how brightness values of the subject are translated into densities of the film emulsion.
The density or characteristic curve typically runs in an S-shape. The actual exposure takes place in its middle, largely straight section. Gamma is the slope value (the gradation) of this straight middle part: a steeper curve means harder contrast, a flatter curve means softer tonal reproduction with richer midtones.
In film exposure, the gamma value determines how strongly the silver particles are blackened depending on the exposure. Classically, the value is given as the angle of inclination of the characteristic curve.
An angle of inclination of 45 degrees is traditionally considered natural contrast reproduction and the ideal value for recording material during shooting; flatter angles result in softer reproduction, steeper angles in harder reproduction.
In video systems, gamma correction was historically applied in the camera to pre-compensate for the nonlinear characteristics of the cathode ray tube (CRT). The transmission is described by the OETF (Opto-Electrical Transfer Function) in recording and the EOTF (Electro-Optical Transfer Function) in playback. A gamma value of 1.0 corresponds to a linear relationship; many classic display environments work with a value around 2.2.
The choice of gamma or tone curve is used to control the contrast and dynamic range of the recording. Modern cameras allow for flexibly adjustable characteristic curves. Log mode and RAW recording deliberately record with very flat gamma to preserve as much tonal information as possible in highlights and shadows, and to determine the final image look in post-production (grading).
Ich verwende Gamma-Korrekturen hauptsächlich in der Postproduktion, um die Bildstimmung zu kontrollieren – ein Gamma von 0.9 öffnet die Schatten für intimere Szenen, während 1.2 dramatischere Kontraste erzeugt. Bei Log-Aufnahmen arbeite ich mit einem standardisierten Gamma von 1.0 und passe erst beim Grading an, um maximale Flexibilität zu behalten.
Gamma-Anpassungen helfen mir, die emotionale Wirkung meiner Szenen zu verstärken – niedrigere Werte schaffen offenere, hoffnungsvollere Stimmungen, höhere Werte erzeugen Spannung und Düsternis. Besonders bei Übergängen zwischen Zeitebenen oder Realitätsebenen nutze ich subtile Gamma-Verschiebungen von 0.1-0.2, um dem Publikum unbewusste visuelle Hinweise zu geben.
Gamma-Workflows beeinflussen meine Budgetplanung minimal, da moderne Kameras und Postproduktions-Software diese automatisch handhaben. Kritisch wird es bei internationalen Koproduktionen, wo unterschiedliche Broadcast-Standards verschiedene Gamma-Anpassungen erfordern – hier plane ich zusätzliche 2-3 Stunden Mastering-Zeit pro Deliverable ein.
1. Was beschreibt „Gamma" am besten?
2. Zu welchem Department gehört „Gamma"?
3. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?
The Lexikon is part of the Filmfarm ecosystem — alongside budgeting (FilmBalance), an industry magazine (FilmCircus) and crew networking (FilmCall, CrewMesh). One shared vocabulary for the whole production.