Digital imagesDigital images can be broken into two categories, artificial or natural. A natural image is something like a photograph or a scanned picture. This is where the image is digitalized by the computer to read then stored or manipulated. Artificial images or graphics are images that have been on the computer using software or other computer processors.
Vector imagesVector images are created on the computer toby using mathematic algorithms to createbasic shapes, lines and arcs and such. Theseshapes are used to make shapes. These can bemanipulated, resized or warped without lossof resolution or quality.
Raster imagerRasters, also called bitmap, are images madeon a computer using pixels. Pixels arearranged in grids where they combine coloursand tones to produce a picture or graphic.Raster imaging is best suited for complex orphotos. The main issue that is presented byraster images is that they are highlydependant on their resolution, meaning thatalteration is difficult without changing theresolution somehow.
Image file formatAll files on a computer takes a certain form ofa specific format. These different formatsallow the computer to determine what the filecontains, i.e. picture, word doc., shortcut, etc.When the file is saved it automatically adds afour letter code that identifies what formatthat the file has been saved as.
.Jpeg.Jpeg stands for JoinPhotographic Expert Groupand is the most common fileformat for pictures andimages. This format is bestsuited for images that haveshading or any slightchanges in colour andlighting effects. This formatunfortunately loses qualitywhen altered.
.GifThe term .Gif stands for GraphicInterchange Format. This format iscross platform and compressed. It’slimited to a colour depth of 8 bits(256 colours) and, unlike .jpeg, willallow some colours to betransparent. This format uses aLossless compression scheme thatallows it to be manipulated withoutaffecting the quality, the losslessscheme .gif’s use is called LZW. This‘no loss’ of quality allows goodquality pictures to be compressedand shared on the internet withoutloss of quality.
.TIF.TIF is a common format usedwhen images and graphics need tobe used by devices other than thecomputer. This allows images to beaccessed through things likeprinting devices without thecontrol of a computer, it iscommonly used for printing thingssuch as logo’s. This format uses thesame compression scheme as .gifs,it has very high resolution but isnot ideal for sharing on theinternet.
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