Images

 Images include graphics, such as backgrounds, color schemes and navigation bars, and photos and other illustrations  An essential part of a multimedia product, is present in every multimedia product

A picture is worth a thousand words  The major make-or-break factor of your multimedia application will always be graphics and design  Potential customers will make an instant judgement, for better of for worse, on the basis of that first impression on the screen

Production of graphics for multimedia applications  In real-life multimedia products there are two key parts of managing the production of graphics: definition of the task and the selection of the personnel  The approach to graphics should be included in the project plan  Your project team may include a graphics artist or an art director  The production team is chosen on the basis of graphics requirements

Production of graphics for multimedia applications  Organizations have quite often a pool of freelance artists; a common situation for graphics and programming

Plan your approach  Whatever is your working method, there will always be a starting point where your page is ”clean”.  Before reaching this point, be sure you have given your project a good deal of thought and planning  To get a handle on any multimedia project, you start with pencil, eraser and paper  Outline your project and graphic ideas first: make a flow chart and storyboard

Colour  A colour image on computer and television screen is made up with red, green and blue; they are called the primary colours  Almost any colour can be made by mixing the three primaries; in a full-colour image each picture element or pixel is built up from varying amounts of three primaries  Shades of grey are produced by making the amount of reg, green and blue light equal; for black there is no light and for white the light is ”full on”  In digital terms there are 256 shades to each of the primaries in a full-colour 24-bit image

Bitmaps  Four bit color palette is capable of displaying 16 colours because there are 16 different combinations of four bits.  With 8 bit colour, there is a total of 256 colours available, with 16 bit colour, a total of is available. When you have 24 bit colour palette, a total of colours is available.  With 32 bit colour we are talking about high quality print graphics (CMYK cyan, magenta, yellow, black).

Bitmaps  The more pixels used in an image the larger the actual file size; the more it consumes memory  You can’t scale a bitmapped image without losing information  Bitmapped images are often used in web pages and multimedia (CD-ROM, DVD, blue ray), but most of the time they are compressed.

Vector graphics  In computer terms a drawing is an image that consists of distinct segments or shapes, called draw objects  It is sometimes referred to as line art  A popular name for drawings in the computer world is vector graphics  The vector graphics are made in drawing programs (e.g. Illustrator)

Vector graphics  In vector graphics, all the elements in the image (circles, rectangles, letters) have characteristics, which can be changed  For example, when you draw a circle in one place, then you draw a rectangle in another place, you can still select the circle and change its size and location  It’s possible because vector graphics are stored as dimensions and formulas, unlike bitmapped images which are stored as individual pixels

Vector graphics  Although most of the graphics on the Web and multimedia are bitmapped, there is a small but important use of draw objects in making animation files  Flash is very popular example  In Flash you have series of still images and Flash contains the information of the moves and changes

Bitmaps vs. Vector Graphics  Remember that the programs can save images in different formats. You are not stuck with the technology you were using in the beginning.  Quite often a bitmap starts out as a set of draw objects; you’ll probably need both technologies  The vector graphic images are smaller in size than the bitmapped

Using what, when and why  In an ideal world, you would always use 24- bit colour images  However, display incompabilities and file sizes (download times) make this sometimes impossible  As well as taking up three times more space of an 8-bit image on your web site or CD-Rom, a 24-bit image takes three times as long to load  Always do retouchíng and compositing operations in 24-bit, although you final delivery may be in 8- or 16-bit

Look before you leap  Any graphic should be checked on the delivery system  Reducing bit-depth, for example, can have all sorts of undesirable side-effects (quantization, posterization)  You can only be sure of compability if you have checked your image on every screen format  Nowadays the platforms are getting closer to each other and they are more compatible (remember the issues with web browsers in the past)

Taking less space  You will usually need to reduce the size of graphics files. There are several methods: Degrading. The size in pixels can be reduced. Reducing the color depth. Compression. JPEG, GIF, PNG

Which graphics format should I use?  You have only two reasons why one format might be better than another 1.The end-user’s browsers may or may not support the format (unlikely) 2.The way the image is compressed lends itself to a particular kind of image GIF for logos, cartoons JPEG for photos, other images with smooth edges

Image compability and quality  Take care that any compression does not noticeably degrade your 24-bit images  From a practical point of view the days of incompatibility for still pictures are over  However, you should know the difference between lossy and lossless compression methods: Lossless: you will not lose data when the image is compressed Lossy: you will lose data when the image is compressed

Asset management  Usually the number of graphics files in a multimedia application is large  Therefore it’s vital that you have a known system of naming files  Do not use too long filenames, they may create problems in some platforms  Try to organize a decent directory structure  Reserve the suffix or extension for the file type

Proofreading  ”There is always one more bug”  Typo is a graphical equivalent for a bug in the code  Even the most experienced typegrapher can make a mistake; be extra careful with names and foreign languages  Proofreading should not be carried out by the same person who wrote the text  Do not rely on spellcheckers

3D drawing and rendering  3D packages are usually object-oriented like a drawing package  Speed of display is often more important than the quality; nowadays the GPU’s (not CPU) have fortunately so much computational power that the limits are not a problem  Surfaces and lightning conditions are set after the objects are drawn  The scene must be rendered to produce the final image or images; this can be very slow

Product Design Games Movie Effects Simula- tions 3D images

(focal lengths)