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 |
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| 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 (permissions-commons@wikimedia.org) | |
| 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 |