Photography terms starting with G

Gamma Colour & Colour Management γ exponent The non-linear relationship between stored numerical values and displayed brightness in a colour space or on a device. Output = Input^γ

Gamut Colour & Colour Management The complete range of colours a device, medium or colour space can produce or record.

Gamut Mapping Colour & Colour Management The process of converting colours from a larger space into a smaller one while preserving as much of the image's appearance as possible.

Gamut Warning Printing, Display & Output A soft-proofing overlay that flags pixels whose colours the destination profile cannot reproduce.

Geotagging Files, Metadata & Workflow degrees Recording the latitude, longitude and sometimes altitude of an image's capture point in its metadata.

Gestalt Principles Composition & Visual Design A set of observations from perceptual psychology describing how the visual system groups separate elements into wholes.

Ghosting Optics, Lenses & Filters Distinct secondary images of a bright light source formed by reflections bouncing between lens element surfaces.

Giclée Printing, Display & Output A marketing term for a fine-art inkjet print, generally implying pigment inks on archival paper.

Gimbal Head Cameras, Formats & Systems kg (load rating) A tripod head that supports a long lens at its centre of gravity, letting it swing weightlessly in two axes.

Gimbal Stabiliser Motion, Video & Creative Techniques kg (payload) A motorised three-axis mount that holds a camera level and steady while the operator moves.

Global Shutter Cameras, Formats & Systems seconds An electronic shutter that starts and stops the exposure for every photosite at exactly the same instant.

Gloss Differential Printing, Display & Output A visible difference in surface sheen between inked and uninked areas of a glossy print.

Glossy Paper Printing, Display & Output Paper with a smooth, highly reflective surface that maximises apparent contrast and colour saturation.

Gobo Lighting & Flash An opaque cut-out or template placed in a light's beam to cast a shaped pattern onto a subject or background.

Golden Hour Lighting & Flash degrees (sun elevation) The period shortly after sunrise and before sunset when the sun is low, and its light is warm, soft and strongly directional. Sun elevation ≈ 0° to 6°

Golden Ratio Composition & Visual Design ratio The proportion of approximately 1:1.618 that has been used in art and architecture as a compositional division. φ = (1 + √5) / 2 ≈ 1.618

Golden Spiral Composition & Visual Design A logarithmic spiral constructed from golden-ratio rectangles, sometimes overlaid on a frame as a compositional guide. r = ae^(bθ)

Golden Triangle Composition & Visual Design A compositional grid formed by a diagonal across the frame and two perpendicular lines from the remaining corners.

Gradient Mask Post-Processing & Retouching A mask that fades an adjustment smoothly along a linear direction, digitally imitating a graduated filter.

Graduated Neutral Density Filter Optics, Lenses & Filters stops (EV) A filter that is dark at one end and clear at the other, used to hold back a bright sky while leaving the land unaffected.

Grey Card Exposure & Metering % reflectance A physical card of known neutral 18 per cent reflectance, held in the subject's light to give both a reliable exposure reading and a white balance reference.

Group f/64 Genres, Movements & Theory A short-lived association of West Coast American photographers formed in 1932 to advocate sharp, unmanipulated photography.

Guide Number Lighting & Flash m at ISO 100 A measure of a flash's power, equal to the product of the correct aperture and the subject distance at a stated ISO. GN = N × d

Terms starting with G