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P
- Panchromatic( Pan )
- Is a photographic emulsion sensitive to all the colours of the visible spectrum and to a certain amount of ultra-violet light. The sensitivity is not uniform throughout the spectrum.
- Panning
- Moving the camera so that the image of a moving object remains in the same relative position in the viewfinder as you take a picture. The eventual effect creates a strong sense of movement.
- Panorama
- A broad view, usually scenic or a series of images stitched together to create a picture wider than what the camera is normally capable of capturing.
- Panoramic camera
- Camera with a special type of scanning lens which rotates. Or a static lens camera with a wide format e.g. 6cm x 17cm.
- Paper base
- Is the support for the emulsion used in printing papers.
- Paper grade
- Is a numerical terminological description of paper contrast: numbers 0-1 soft; numbers 2 normal; number 3 hard; number 4-5 very hard; number 6 ultra hard. Similar grade number from different manufactures do not have the same characteristics.
- Paper safe
- Is a light-tight container for unexposed photographic papers, with an easy open positive closing lid.
- Parallax
- The difference in point of view that occurs when the lens (or other device) through which the eye views a scene is separate from the lens that exposes the film.
- Parallax error
- Occurs when shooting very close up with a viewfinder camera. The photographer does not see an accurate indication of the subjects position relative to the lens, so parts of the subject that he or she thinks will be photographed are missing on the final photograph. Parallax error is overcome in more expensive compact and viewfinder cameras which adjust the viewfinder to compensate for the distance the subject is away from the camera.
- Parallax focus
- Focusing system in some compact cameras that compensates for the difference between viewfinder and lens placement.
- Parallel cable
- The cable connection between the computer and another device's parallel ports ( usually a printer ), which allows a computer to send several bits of data simultaneously.
- Parallel port
- A connector on your computer that allows you to connect to other devices, such as a printer . Another name for parallel port is LPT port.
- Parallel Processing
- When an array of processors or segments of the CPU work at the same time to speed processing or multi-task.
- Path
- A path is an overlay that sits on top of your image, allowing you to work with it.
- PCMCIA card
- ( Personal Computer Memory Card International Association ) card. used in digital cameras to transfer photos to a notebook or PC.
- PDF
- (PortableDocumentFormat) is a file format that has captured all the elements of a printed document as an electronic image that you can view, navigate, print, or forward to someone else. PDF files are created using Adobe Acrobat (NOT the free reader), Acrobat Capture, or similar products. To view and use the files, you need the free Acrobat Reader, which you can easily download. Once you've downloaded the Reader, it will start automatically whenever you want to look at a PDF file. PDF files are especially useful for documents such as magazine articles, product brochures, or flyers in which you want to preserve the original graphic appearance online. A PDF file contains one or more page images, each of which you can zoom in on or out from. You can page forward and backward.
- Peripheral
- A term used to collectively describe computer accessories such as printers, modems, scanners, etc.
- Perspective
- The angle or level from which the photographer takes the photograph; the camera and photographer's "point of view".
- ph
- A measure of acidity or alkalinity. pH7 is neutral; lower numbers indicate increasing acidity, while higher numbers indicate increasing alkalinity. pH control is an essential aspect of photographic chemistry, and one which is often neglected.
- Phosphor
- The chemical substance on the inside face of a computer screen that illuminates when electrically charged. The colour accuracy and luminance values of phosphors change over time, necessitating regular monitor calibration if consistent colour is required.
- Photo CD
- A popular storage method for digital images. In the basic Kodak Photo CD configuration, five different levels of image quality are stored for each in an Image Pac.
- Photo diode
- A semi conductor measuring or converting light into electrical current, commonly used in scanners and CCD's
- Photomontage
- A photographic composition assembled from pieces of different photographs or of different negatives, closely arranged or superimposed upon each other. Sometimes graphic material is added to the combination.
- Photoshop
- A sophisticated software program, produced by Adobe Systems, for editing and processing of images.
- Photosite
- A single photosensitive element in a CCD which translates to one pixel in the resultant image. Also known as a CCD Element
- PICT
- Macintosh picture. A storage format for digital images designed for the Macintosh.
- Pigment
- Particles that absorbs and reflect light and appear coloured to our eyes. The substance that gives ink its colour.
- Pincushion distortion
- A lens aberration or defect that causes straight lines to bow inward toward the center of the image.
- Pinhole
- 1. A small clear spot on a negative usually caused by dust on the film during exposure or development or by a small air bubble that keeps developer from the film during development. 2. The tiny opening in a pinhole camera that produces an image.
- Pixel
- Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected. The number of bits used to represent each pixel determines how many colours or shades of gray can be displayed. For example, in 8-bit colour mode, the colour monitor uses 8 bits for each pixel, making it possible to display 2 to the 8th power (256) different colours or shades of gray. On colour monitors, each pixel is actually composed of three dots - a red, a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make colour pixels appear fuzzy
- Pixel dropping
- A subsampling technique used to reduce the number of pixels in an image by dropping every nth pixel from the scan.
- Pixel Modulation
- A process used in printing which changes the brightness of individual pixels by changing the pixel size.
- Pixel skipping
- A means of reducing image resolution by simply deleting pixels throughout the image.
- Pixelization
- The stair-stepped appearance of a curved or angled line in digital imaging. The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the image. Also known as the "jaggies".
- Plane of focus
- The point in a camera where all the light rays converge, forming a sharp image. In a camera, this corresponds to the film plane.
- Plasma display
- A display screen that has gas contained between two panels. When specific x-axis ( horizontal ) and y-axis ( vertical ) dots on the panels are electrically charged, the gas in that area glows.
- Platen
- The glass scanning region on a flatbed scanner.
- Platform
- The brand or computer type you are using, i.e., a Windows platform or MAC platform.
- Plug and play
- The ability to install equipment with little or no setup.
- Plug-in
- The plug-in architecture was first popularized by Adobe Photoshop and is now the de facto standard for all major imaging programs. Unlike TWAIN it allows more flexibility in design so acquire, export, and specific task can be performed within a software application. This is the preferred choice of operation in the Macintosh and 'Power User' computers. Plug-In ideology has spread to other applications like Netscape Navigator, Macromedia Director, and so on. Not all plug-ins work with all products, specific interfaces are required for different types of software. Plug-Ins are also software version dependent.
- PMT
- Photo Multiplier Tube. The light sensing devices generally used in drum scanners.
- PNG
- Developed as a patent-free alternative to GIF, the Portable Network Graphics (PNG) format is used for losslessly compressing and displaying images on the World Wide Web. Unlike GIF, PNG supports 24-bit images and produces background transparency without jagged edges; however, some older versions of Web browsers may not support PNG images. The PNG format supports grayscale and RGB colour modes with a single alpha channel, and Bitmap and indexed-colour modes without alpha channels. PNG uses the saved alpha channel to define transparency in the file.
- Point and shoot
- A term used for a simple, easy to use camera with a minimum of user controls. Generally the user turns the camera on , aims it at the subject and presses the shutter button. The camera does everything automatically.
- Polarization
- The use of specific filters to control the direction light travels. Effects are the reduction of glare and reflections and the saturation of colours, especially in landscapes.
- Polarizing filter
- Usually indicates a linear polarizing filter. A linear polarizing filter eliminates various degrees of reflected light from glass, water, plastic, paper and similar surfaces. It can also eliminate light reflections from vapours or floating dust to emphasize a blue sky. Polarizing filters transmit light waves that vibrate in a single direction only; the effect can be seen in the viewfinder as the filter is rotated. (Used to make clouds look full and puffy and skies dark blue)
- Polaroid back
- A camera back that uses instant film for proofing a scene (checking lighting, composition & basic exposure ) before shooting with traditional film.
- Ports
- Plugs or connectors into which cables are attached.
- Positive
- The opposite of a negative for example an image with the same tonal relationships as those in the original scan. Most prints and slides are positive.
- Posterization
- A photographic or digital graphic effect arising from reducing the number of continuous tones in an image. Can be a deliberate effect or a result of over-manipulation or compression in a digital image.
- Posterize
- To achieve the impression of continuous tone we need to reproduce 256 differentiation's of tone from white to black. If we break down the tonal range into fewer differentiation's you begin to see the breaks between the individual tones.
- PPI
- Pixel Per Inch. The frequency of the number of samples used to display an image on a computer monitor.
- Prescan
- A quick, low resolution preview scan of an image to be scan.
- Presoak
- To soak film briefly in water prior to immersing it in developer.
- Primary colours
- The set of colours that can be mixed to produce all the colours in a colour space; in additive systems they are red, green, and blue, while in subtractive systems they are cyan, magenta, and yellow.
- Printer resolution
- The amount of detail a printer or imagesetter will reproduce, measured in dots per inch (dpi).
- Prism
- Triangular-shaped glass or other transparent material. When light is passed through a prism, its wavelengths refracts into a rainbow of colours. This demonstrates that light is composed of colour, and indicates the arrangement of colours in the visible spectrum.
- Process colours
- The four colours (cyan, magenta, yellow, and black) that are combined to print a wide range of colours. When blended, they can reproduce only some of the colours found in nature.
- Process control
- The stability of a manufacturing process that assures the products produced sable and consistent.
- Profile
- An ICC description of a particular imaging input or output device that allows the Colour Management Software to apply the proper transformations to the image file to match the specific limitation of the device.
- Program mode
- An automatic exposure mode in which the camera adjusts all aspects of exposure.
- Progressive CCD
- CCD specially designed for digital cameras, the shape of progressive CCD pixels being square thereby making them ideal for photography.
- Progressive Scan
- A non-interlaced refresh system for monitors that cuts down on CRT flicker.
- Proof
- A test print made for the purpose of evaluating density, contrast, colour balance, subject composition, and the like.
- Proprietary
- The design of programs, systems or equipment that are owned by an entity. This technology may be licensed for use in other applications or systems.
- Proxy
- A representative version or sample of a larger image.
- Proxy Image
- A low resolution image used in any software programs to show the effects of changes without performing transformations on high resolution files.
- PSD
- The native file format of the Adobe Photoshop graphical editing application. Adobe Photoshop is a standard editing application in the print and internet media worlds.
- Pull processing
- Decreasing the effective speed of film, often to compensate for a mistake in setting ISO. It is usually done by decreasing the development time or the temperature of the developer.
- Push
- To expose film at a higher film speed rating than the normal, then to compensate in part for the resulting underexposure by giving greater development than normal. This permits shooting at a dimmer light level, a faster shutter, or a smaller aperture that would otherwise be possible.
- Push processing
- Extending development time, usually to compensate for underexposure caused by a film being upgraded to permit a faster shutter than the light allows.
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