1. An Introduction to Computer Graphics B.Sc. (Hons) Multimedia ComputingMedia Technologies

2. Agenda Image Acquisition Vector Graphics Bitmapped Graphics Layers File Formats Optimisation and Deployment Software B.Sc. (Hons) Multimedia ComputingMedia Technologies

3. Image Acquisition B.Sc. (Hons) Multimedia ComputingMedia Technologies Scanner Digital Camera Computer Artwork Digital Capture or Transfer Library Material

4. Image Quality: Scanners Optical Resolution – determined by the number of Charge Coupled Devices (CCDS) Mechanical Resolution – distance scanner travels each time to take a vertical snapshot of the image Interpolation between snapshots Mechanical construction may affect mechanical resolution Integrated or dedicated flatbed B.Sc. (Hons) Multimedia ComputingMedia Technologies

5. B.Sc. (Hons) Multimedia ComputingMedia Technologies Types of Scanners Flatbed Integrated ‘all in one’ i.e scanner, printer, copier

6. B.Sc. (Hons) Multimedia ComputingMedia Technologies Different Scanners give different images Microtech Flatbed Dell ‘all in one’ i.e scanner, printer, copier

7. Dell Scanner

8. Microtech Scanner

9. Image Quality: Digital Cameras Conventional ‘enprint’ from a 35mm negative has the equivalent of some four million pixels worth of picture information. Digital camera therefore requires at least 4 Megapixels to equal 35mm resolution. Nikon and Canon manufacture high-end (pricey) 35mm DSLRs ‘Professional’ cameras (medium format ) use 6cm x 6cm negatives. - B.Sc. (Hons) Multimedia ComputingMedia Technologies

10. B.Sc. (Hons) Multimedia ComputingMedia Technologies Digital Cameras : Nikon D3 (12 Mega Pixels) First Full-frame Nikon DSLR (October 2007)

11. B.Sc. (Hons) Multimedia ComputingMedia Technologies Digital Cameras : Pentax Optio (5 Mega Pixels)

12. B.Sc. (Hons) Multimedia ComputingMedia Technologies

13. Vector Graphics Mathematically prescribed Wont loose resolution when scaled Give very lightweight file sizes Limited picture information for photorealism File Formats.wmf,.swf, cgm Software Adobe Illustrator, Adobe Freehand Bitmap and Vector editing features in Flash and Fireworks B.Sc. (Hons) Multimedia ComputingMedia Technologies

14. Bitmapped Graphics Allow for high-definition photorealistic images. Image encoded on a pixel by pixel basis. Image resolution degraded when scaled Supports lossless compressions algorithms File Formats -.BMP,.GIF,.JPG,.TIF.TGA Software Adobe Photoshop ( with ImageReady) Macromedia Fireworks PaintShop Pro (Shareware) B.Sc. (Hons) Multimedia ComputingMedia Technologies

17. GIF = G raphics Interchange Format 2 – 256 colours compressed before stored Lossless compression algorithm Two common types GIF87a and GIF89a GIF89a Supports transparency Supports animation sequence License issues if supported in a graphics software package B.Sc. (Hons) Multimedia ComputingMedia Technologies

18. B.Sc. (Hons) Multimedia ComputingMedia Technologies GIF 256 : 800 x 600 : 256 Colours: File Size 164KB

19. JPEG = Joint Photographic Experts Group Specifically designed for photographic images. Supports up to 24 bits per pixel Lossy compression algorithm Image quality chose when exported from graphics Quality versus file size B.Sc. (Hons) Multimedia ComputingMedia Technologies

20. B.Sc. (Hons) Multimedia ComputingMedia Technologies JPEG : 800 x 600 : 80 % : File Size 71KB

21. B.Sc. (Hons) Multimedia ComputingMedia Technologies JPEG : 800 x 600 : 60 % : File Size 37 KB

22. B.Sc. (Hons) Multimedia ComputingMedia Technologies JPEG : 800 x 600 : 30 % : File Size 12 KB

23. GIF or JPEG ? To which format should you export your images? The general rule is if the image was created with a computer package from scratch - then save as a GIF If the image is of a real picture - scanned or from a digital camera - save as a JPEG B.Sc. (Hons) Multimedia ComputingMedia Technologies

24. Layers and Construction Files Layers control accessibility and aid workflow Lock layers Hide layers Use mask layers for visual effect Layers are provide recipe file for future editing and revisions Layers are lost (flattened) when the image is exported to a given bitmap file format Construction file has lost of information so has a very large file size compared to exported image format B.Sc. (Hons) Multimedia ComputingMedia Technologies

25. Optimisation & Deployment Control over compression (.JPEG) Palette depth (.GIF) Balance of picture quality versus file size For web deployment use ‘Export for web’ Never deploy the construction (layered) file! Deploy for non-BroadBand audiences (for now) B.Sc. (Hons) Multimedia ComputingMedia Technologies