Photography terms starting with D

Daguerreotype Film, Darkroom & Historic Processes The first commercially successful photographic process, producing a unique, highly detailed image on a polished silvered copper plate.

Dark Current Sensors & Digital Capture e⁻/s Charge that accumulates in a photosite from thermal energy rather than from light, growing with exposure time and temperature.

Dark Frame Sensors & Digital Capture An exposure made with the shutter closed, at the same duration, temperature and ISO as the real image, used to characterise sensor noise.

Darkroom Film, Darkroom & Historic Processes A light-tight room equipped for processing film and making prints.

DCP Profile Colour & Colour Management A DNG camera profile, the file format used to describe a camera's colour response to raw processing software.

Dead Pixel Sensors & Digital Capture count A photosite that records no signal at all, appearing as a permanently black point in every image.

Deconvolution Sharpening Post-Processing & Retouching % A sharpening method that models how the image was blurred and mathematically reverses that blur.

Deep Depth of Field Focus & Depth of Field m A wide zone of sharpness in which foreground, subject and background all hold detail.

Dehaze Post-Processing & Retouching % A control that removes or adds atmospheric haze by estimating and correcting for scattered light.

Delta E Printing, Display & Output ΔE A numerical measure of the perceived difference between two colours, used to quantify display and print accuracy. ΔE = distance in CIELAB space

Demosaicing Sensors & Digital Capture The process of reconstructing a full-colour image from the single-colour samples recorded under a colour filter array.

Densitometer Film, Darkroom & Historic Processes density units An instrument that measures the optical density of a negative, transparency or print.

Density Film, Darkroom & Historic Processes density units A measure of how much light a processed negative or print blocks, expressed logarithmically. D = log₁₀(1 / transmittance)

Depth Cues Composition & Visual Design The visual signals — overlap, relative size, convergence, haze and blur — that let a flat image suggest three dimensions.

Depth of Field Focus & Depth of Field m The range of distances in front of and behind the plane of focus that appears acceptably sharp in the final image. DoF ≈ 2u²Nc / f²

Depth of Field Preview Cameras, Formats & Systems A control that stops the lens down to the working aperture so the actual depth of field can be seen before exposure.

Depth of Field Scale Focus & Depth of Field m / ft Markings on a lens barrel showing the near and far limits of sharpness for each aperture at the set focus distance.

Depth of Focus Focus & Depth of Field µm The tolerance in sensor position, on the camera side of the lens, within which the image stays acceptably sharp. ≈ 2Nc

Desaturation Colour & Colour Management % Reducing the intensity of colour, either globally toward monochrome or selectively within a range.

Developer Film, Darkroom & Historic Processes minutes at °C The chemical solution that converts exposed silver halide crystals into metallic silver, making the latent image visible.

Diagonal Lines Composition & Visual Design Lines running at an angle to the frame edges, which introduce energy and a sense of movement.

Diagonal Method Composition & Visual Design A compositional approach placing points of interest on the 45-degree bisectors drawn from each corner of the frame.

Diffraction Optics, Lenses & Filters µm The spreading of light waves as they pass the edge of an aperture, which softens the image at small f-numbers. d = 2.44 × λ × N

Diffraction Limit Optics, Lenses & Filters f-stops The aperture beyond which diffraction, rather than lens design or sensor resolution, becomes the factor limiting sharpness. N_limit ≈ pixel pitch / 1.22λ

Terms starting with D