Wikipedia:Featured picture candidates/Glossary

This page contains a glossary of terms, abbreviations and acronyms frequently used at Wikipedia:Featured Picture Candidates and Picture peer review.

Term	Meaning and/or link	Brief definition
AF	Autofocus	ability of a camera to focus on a subject automatically (cf. MF)
AOV	Angle of view	angular extent of a scene that is imaged by a particular camera or lens (cf. FOV)
Artefact/Artifact	Digital artefact	Foreign features in an image that are absent from the original capture; compression artefacts are most commonly encountered.
Blown (or blown highlights)	Clipping	A situation where the brighter parts of an image are totally white (or any one color channel), causing a loss of highlight detail and an often unappealing look to the image. This is commonly seen when shooting into a bright section of the sky for example
CA	Chromatic aberration	A type of distortion in which a lens fails to focus all colours to the same point; often seen as "fringes" of colour along boundaries separating darker and brighter parts of an image
Clipped	Clipping	A blown white or crushed black (blocked up shadow, crushed shadow)
Cloning		duplicating parts of an image so as to cover up other, usually faulty, parts, or introducing new elements to an image, copied from another
Colour cast	Colour cast	A tint of a particular colour, usually unwanted, which affects the whole of a photographic image evenly
Commons	Wikimedia Commons	A media repository and resource for the Wikimedia projects
Comp/composition	Composition (visual arts)	The arrangement of items within the boundaries of the image
Copyvio		A copyright violation—an uploaded file erroneously marked as public domain or otherwise freely licensed when it is not; such files are often deleted once the error is discovered.
Cropping	Cropping (image)	The narrowing of the boundaries of the image; this usually means cutting off part of the image at the top, bottom, left and/or right, to focus more on the central subject or to balance composition.
D&R	Delist and replace	delist nomination(s) where one image has been proposed to usurp another one's Featured Picture status (and, usually, placement in articles) a vote that indicates being in favour of such an usurpation: "several people voted D&R on that nomination" phrase sometimes used to indicate this preference: "D&R. Username (talk) Foo Date"
Digicam	Digital compact camera	a small, "compact" digital camera, but more usually refers to any camera below a DSLR
Dithering	Dithering#Examples
DOF	Depth of field	the amount of a photographed subject that appears to be in focus
Downsampling		scaling down an image, usually to average out noise or to make an image appear sharper; now disfavoured at FPC
De minimis	De minimis	acceptable inclusion of copyrighted material as a small portion of a newly copyrighted image, provided that the inclusion is accidental and minimal
DSLR	Digital single lens reflex camera	an exchangeable-lens digital camera with full manual capability and a large sensor; generally produces superior photographic quality
Dust spots		Undesirable diffuse shadow spots or dark points on digital photographs, caused by dust and other particles on the surface of the image sensor; can be removed from an image by cloning
Dynamic range	Dynamic range	luminance range of a scene being photographed, or the limits of luminance range that a given digital camera or film can capture
en:wiki	English Wikipedia	the English language Wikipedia (cf. WP)
enc	Encyclopaedic	of or having encyclopaedic value
EV	encyclopaedic value	Adding information or value to the Wikipedia encyclopaedia
Exposure blending	-	technique to compress greater dynamic range into a screen-viewable low-dynamic-range image by combining an ‘exposure stack’ of images without the intermediate step of an HDR image
Exposure bracketing	Exposure bracketing	photographic technique where a set of images are taken at slightly different exposures, usually when dealing with a scene with high contrast. The best image of the set may be chosen, or the set may be used in an "exposure stack" to create an HDR image
FoP/freedom of panorama	Freedom of panorama	copyright provision that allows taking pictures of buildings and sculptures in some jurisdictions (countries)
FOV	Field of view	that part of the world that is visible through a camera at a particular position and orientation in space (cf. AOV)
Focus stacking	Focus stacking (see also Focus bracketing)	single image created from a ‘stack’ of original images taken at slightly different focal lengths, allowing a far greater depth of field than would be possible in a standard single photograph
FP/FPs	Featured pictures	images that meet, determined by the Wikipedia community, a range of technical and encyclopaedic criteria, representing a preferred selection of the encyclopaedia's available media
FPC	Featured picture candidates	process by which images are adjudged by the community as to whether they meet the criteria to be Featured pictures
FPC Talk	Featured picture candidates talkpage	discussion or talk page for issues relating to the Featured picture candidates project
Framing		refers to composition or cropping, or a combination of the two
Ghost/ghosting		artefacts seen with HDR or stitching usually where an object in the picture moved between frames and when combined you see more then one of that object in the final picture, some appearing like semitransparent ghosts
GIF	Graphics interchange format	image compression format used mainly for diagrams and simple animations with a limited colour palette
GIMP	GNU Image Manipulation Program	a free graphics editing program often used as an alternative to the expensive commercial program Adobe Photoshop
Halftoning	Halftone
Halo	Edge enhancement	Bright area around dark objects that results from sharpening. Considered an artefact and defect.
HDR	High dynamic range	imaging technique that allows a greater dynamic range between light and dark areas of a scene than a normal photograph would allow. This usually involves ‘stacking’ a set of images created in an exposure bracket. An HDR image is not directly viewable on conventional displays. It has to be transformed into a low dynamic range image by means of Tone mapping.
Head room	Head room	space left in a picture above the subject of interest, usually above a subject's head in a portrait
Healing		duplicating patterns (texture) to cover up other, usually faulty, parts; healing preserves the local hue and saturation of the destination area
Histogram	Image histogram	in the context of graphics, a bar chart representation of the brightness values present in an image, and/or of different colour parameters. Can show the presence of blown highlights or clipped shadows, or give hints as to the intensity of previous colour manipulation in an image.
IMO/IMHO	in my opinion/in my humble opinion	commonly used acronym in text based communications
IQ	Image quality	subjective measure of the technical quality of an image, based on such things as focus, sharpness, noise levels, etc
ISO	Film speed	This is the measure of a photographic film's sensitivity to light; the effect is produced in digital cameras by altering the sensor’s signal gain. In general, while being more sensitive to light, higher ISO settings lead to degraded image quality, such as increased noise and reduced sharpness and detail
Lead room	Lead room
Lens flare	Lens flare
LoC	Library of Congress
JPG/JPEG	Joint photographic experts group	The most commonly used image compression format for photographs. When used correctly it allows image filesizes to be significantly reduced without noticeable loss in quality
MF	Manual focus	using a manual technique to focus the camera on the subject (cf. AF)
MP	Megapixel	Literally one-million pixels, it is used as a measure of how many pixels contained in an image, and gives a rough approximation to the level of detail the image may contain. The megapixels in an image can be found by multiplying the number of pixels in the width by the pixels in the height, and dividing by a million
Noise	Image noise	random variation of brightness or colour information in images produced by the sensor and circuitry of a scanner or digital camera. This is usually most pronounced in darker or shadow areas of an image, and is seen most often in images taken at high ISO settings
NPOV	Neutral point of view	a standard Wikipedia stating that information provided should not expose any particular point of view; this applies to images as well
NR	Noise reduction
OOF	Out of focus	parts of an image that are not in focus, or an image that has not been focussed properly
OTRS		refers to the Open-source Ticket Request System, and in the context of FPC, refers to the possibility for image submitters to grant rights to use an image by sending an email to the Wikimedia Foundation ([email protected])
Oversharpen	Edge enhancement	to degrade image quality by applying too much sharpening, usually evidenced by "halos" around contrast boundaries or unnatural textures (cf. Sharp/sharpness)
Pano	Panorama	widescreen style image (i.e., an image with a large FOV) typically produced by using software to ‘stitch’ together a number of separate photos taken while panning across the scene
PD	Public domain
pd-art		public domain license (tag) applied to reproductions of artworks
pd-gov/PD-USGov		public domain license (tag) applied to works produced by the United States government and which are, by default, in the public domain
pd-old		Public domain license (tag) applied to works whose copyright has expired. Typically old fine art or book illustration.
Perspective correction	Perspective control	Typically required when tall structures are photographed from a low or high angle/position with standard lenses (rather than the more appropriate tilt-shift photography lenses), and the structure in the resulting photograph seems to be reclining away from the viewer. Correction can be carried out in standard graphics programs such as GIMP.
PNG	Portable network graphics	An alternative image compression format to JPG. Though not as common it is a lossless format while JPG is lossy
Point and shoot	Point-and-shoot camera
Posterisation	Posterisation	posterization involves the conversion of what should be a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another
PP	Post-processing	editing done to an image following image capture but before uploading a final version using a program such as Photoshop or GIMP
PPR	Picture peer review	a page that can be used to seek feedback on images prior to nominating them at FPC
Purple fringing	Purple fringing
PS	Photoshop	Adobe Photoshop is a photo editing program developed and published by Adobe Systems
RAW	Raw image format	image format used in DSLRs and some high-end digicams that captures far greater information for a photo allowing more extensive post-processing of the image
Res/resolution (also high res, low res, etc)	Image resolution	the level of detail an image holds, usually measured as the number of pixels/megapixels, although this is not always a precise measure of actual detail due to differences in image quality
Seams		borders of individual images in a stitch
Sharp/sharpness	Acutance	extent to which the edges on objects in an image appear to be clearly defined (cf. Soft; see also Oversharpened)
Soft/softness	Acutance	extent to which the edges on objects in an image appear to be poorly defined (cf. Sharp)
Stitch	Image stitching	to combine a number of separate images into a single panoramic image
Stitching error		where stitching has been inaccurate and resulted in discontinuous features or repeated objects (twins)
SVG	Scalable vector graphics	image format used in drawings and diagrams that uses mathematical formulae rather than bitmaps to create the image, meaning the image can be infinitely resized without losing image quality
Thirds	Rule of thirds	proposes that in a well-composed image, were it divided into three equal parts either horizontally or vertically, the object of interest would be on one of the dividing "lines" or an intersection; generally disregarded on Wikipedia, where compositions that centre the subject are often preferred
TIFF	Tagged Image File Format	A lossless file format that retains all information in an image. Rarely used on the internet due to the large file sizes it produces
Tilt		At FPC, usually a synonym for rotation. Not to be confused with tilt-shift photography.
Tone mapping	Tone mapping	The process that creates a screen-viewable low dynamic range image from an HDR image. Various operators exist for this transformation, and their choice can greatly influence the appearance of the final image (such as local contrast, and saturation)
Twins		where people or elements appear more than once in a stitched image; considered a stitching error
Upsampling		increasing the number of pixels in an image without increasing the information content
Vignetting	Vignetting	reduction of an image's brightness or saturation at the edges and especially the corners compared to the image centre
VP	Valued pictures	Images that were determined by the community to meet the criteria of having high encyclopaedic value. The project is now defunct.
VPC	Valued picture candidates	process (now defunct) by which images were adjudged by the community to be valued pictures
WB	White balance	correct reproduction of colours in an image – in essence whether or not whites appear to be white
WP	Wikipedia	the free, web-based, collaborative, multilingual encyclopaedia project supported by the non-profit Wikimedia Foundation