HA1 - Technical File – Raster and Vector Images Raster Images Raster images are a bunch of dots called pixels, each pixel is a small coloured square. When an image is scanned, the image is converted to a collection of pixels called a raster image. Scanned graphics and web graphics (JPEG and GIF files) are the most common forms of raster images. The resolution of a raster image or scanned image is expressed in terms of the dots per inch or dpi. A printer or scanner's resolution is also measured in dots per inch. This is an example of a raster image.
HA1 - Technical File – Raster and Vector Images Vector Images A vector image is a collection of connected lines and curves that produce objects. When creating a vector image in a vector illustration program, node or drawing points are inserted and lines and curves connect notes together. This is the same principle as "connect the dots". Each node, line and curve is defined in the drawing by the graphics software by a mathematical description. Every aspect of a vector object is defined by math included node position, node location, line length and on down the line. Text objects are created by connecting nodes, lines and curves. Every letter in a font starts out as a vector object. Vector images are object-oriented while raster images are pixel oriented. A vector object will have a "wireframe" underneath the colors in the object. In a vector object, colors are like clothes over the top of a skeleton. CorelDRAW and Illustrator create text and objects using vectors that can be easily manipulated. This is an example of a vector image, the quality has much improved over the raster image version of this.
HA1 - Technical File – Anti-aliasing Anti-Aliasing is a method of fooling the eye that a jagged edge is really smooth. Anti-Aliasing is often referred in games and on graphics cards. In games especially the chance to smooth edges of the images goes a long way to creating a realistic 3D image on the screen. Remember though that Anti-Aliasing does not actually smooth any edges of images it merely fools the eye. Like a lot of things they are only designed to be good enough. If you can't tell the difference then that's fine. The letter on the left is a blown up letter a with no anti-aliasing. The letter on the right has had anti-aliasing applied to it. In this blown up form it looks like its simply blurred but if we reduce the size down to a more standard size you may see the difference. The letter A on the right with the size reduced.
HA1 - Technical File – Resolution Image resolution describes the detail an image holds. The term applies to raster digital images, film images, and other types of images. Higher resolution means more image detail. Image resolution can be measured in various ways. Basically, resolution quantifies how close lines can be to each other and still be visibly resolved. Resolution units can be tied to physical sizes (e.g. lines per mm, lines per inch), to the overall size of a picture (lines per picture height, also known simply as lines, or TV lines), or to angular subtenant. Line pairs are often used instead of lines; a line pair comprises a dark line and an adjacent light line. A Line (or TV line, TVL) is either a dark line or a light line. A resolution of 10 lines per millimetre means 5 dark lines alternating with 5 light lines, or 5 line pairs per millimetre (5 LP/mm). Photographic lens and film resolution are most often quoted in line pairs per millimetre. Above is an illustration of how the same image might appear at different pixel resolutions, if the pixels were poorly rendered as sharp squares (normally, a smooth image reconstruction from pixels would be preferred, but for illustration of pixels, the sharp squares make the point better).
HA1 - Technical File – Aspect Ratio The aspect ratio of an image is a number to represent it’s width by its height e.g 4:3. this number would mean the width is larger than the height meaning it would be a longer image rather than a taller one. These are both aspect ratios.
HA1 - Technical File – File Formats File formats are things added to the end of a file name so we can see what type of file it is and what it can be used on. These are things such as .doc which tells us it’s a word document and can be used on microsoft words and other word processors. File types include: gif: an animated image, used on something such as windows movie maker. Jpeg: standard image file, can be used on almost anything which uses images. Tiff: file format for storing images, used mainly on Adobe software. Eps: standard graphics file format for exchanging images, drawings (such as a logo or map) or even layouts of complete pages. PSD: files that are used on photoshop and is usual file type of an unfinished photoshop image that can be opened and edited straight away. PDF: an internet format used for electronic distribution because it maintains the look of the document and keeps the fonts, colours etc.
HA1 - Technical File – Colour Models A colour model is an abstract mathematical model describing the way colours can be represented as tuples of numbers, typically as three or four values or colour components. When this model is associated with a precise description of how the components are to be interpreted (viewing conditions, etc.), the resulting set of colours is called colour space. This section describes ways in which human colour vision can be modelled.
HA1 - Technical File – Adobe Photoshop Adobe Photoshop is an adobe software used for image manipulation and editing and is one of the best software's for that job. It has endless features on it for editing images such as filters to change the way images look, clone tool to remove things from images and make it look like it never was removed and other features. It is often used to make celebrities look more attractive on magazines and adverts to make it more appealing to the audience.
HA1 - Technical File – Adobe Illustrator Adobe Illustrator is an Adobe software used mainly for the creation of images but can also has a few features for editing images. It allows you to create images neatly and in detail with its many features. Features include being able to create many shapes to your preference, advanced pen tools, advanced text tools and more.
HA1 - Technical File – Adobe InDesign Adobe InDesign is an adobe software used to create newspapers, flyers, posters, magazines and more. It has the features to create documents in the layout of newspapers, magazines etc and has many different text features as well which can be used to make the document look accurately like what it’s meant to look like.