Interactive Media Terminology

by interactivemediasw

Raster Image


A Raster Image is a Dot Matrix Data Structure; this represents a rectangular grid of pixels (points of colour) this can be viewed on paper, on a monitor or any other display medium. Raster Images are stored in image files.

A Bitmap is a technical characterisation by the width and height of the image in pixels or per pixels depending on the number of bits.



Gifs are compressed files that are often used for pictures. GIFs are often used for images that have simple shapes and have a maximum of 256 colours. GIFs are often formatted to be used as graphics for websites, for example a interactive banner advertisement. Quality of the images is often lost when GIFs are saved this could be changed if the files are compacted using lossless compression this means the image will not lose its quality is size is reduced.



TIFF stands for Tagged Image File Format. TIFFs are mostly used for storing very large, high quality images, which explains why the maximum size a TIFF can obtain is 4GB. A TIFF file is identified by a .tiff or a .tif file TIFF files are used to store extremely large, high quality images which include images such as manipulation programs and 3-D imaging applications.



JPGs (JPEG) is short for Joint Photographic Expert Group. JPGs format is lossy, it allows file reduction which loses little or no quality. When file sizes get too small it will come out of focus. When saving JPG files whether for the web or a screensaver you must choose whether you prefer quality or size.


PSD means Photoshop Document, it is a layered image file that is used in Adobe Photoshop, it is the default format in which Photoshop uses to save data. PSD allows the user to work with an images individual layer, even after the file has been saved. When the image has been completed Photoshop allows the user to flatten the layers and convert the image into a .JPG, .GIF, .TIFF ect, however once this has been done, it cannot be reversed therefore the user will no longer be able to work with the images layers.


Lossless compression allows all data that was originally in the file to remain after the file is uncompressed; all information is completely restored for example this technique is used on spreadsheet files as losing financial data could pose a threat.  The GIF file provides lossless compression.

Lossy compression reduces files by deleting certain information permanently. When the files uncompressed only parts of the original information is still there. Lossy compression is mainly used for video and sound this is because it is less likely for users to notice if a certain amount of information has been lost. JPEG uses lossy compression.



Vector images are sometimes called geometric files. Vector images are created using mathematical statements, these place lines and shapes in a two-dimensional or three-dimensional space. A vector file describes a series of points to be connected. Vector files are converted into a raster graphics image this uses bitmap to find a direct place to display space.



A range of gray shades from white to black, which are used in a monochrome display or anything that is printed. The darkest shade is black, (which is a no show of reflected light) and the lightest shade is white (which is the full transmission of light at all visible wavelengths).



RGB, which stands for Red, Green and Blue, is a system that represents the colors that are used on a computer screen. RGB can be mixed into various amounts.

YUV is a color space, which is often used as part of a color image pipeline. YUV is a color encoding system, which is used for analog television such as PAL. The difference between RGB and YUV is that YUV represents the human perception of color similarly compared to the average RGB model that is used.

HSV is an abbreviation for Hue Saturation Value. It is best when working with digital images to use HSV, over RGB; this is because of the different ways the models attempt to find how humans recognize color.

Monochrome is a photograph or picture, which is developed in varying tones of only one color.