Multimedia Specification Design and Production

1. Multimedia Specification Design and Production 2012 / Semester 1 / L4 Lecturer: Dr. Nikos Gazepidis gazepidis@ist.edu.gr

2. Graphic File Formats • Objectives • Understand the difference between two major categories of computer graphic images • Investigate the differences between various file formats • Generalize formats to the type of software that creates them • Establish a philosophy of use for various graphic file formats

3. Graphic File Formats Native File Format

4. Graphic File Formats Bitmapped Formats • Images are created by individual pixels displayed in various colors. • Remember, each pixel can hold up to 24 bits (3 bytes) of color information • Bitmapped formats have a fixed resolution • Can NOT be resized without some effects on the clarity of the image

5. Graphic File Formats Bitmapped Formats • Bitmapped formats are best suited for “photographic” quality images • Scanners and digital cameras acquire images in bitmapped formats

6. Graphic File Formats Common Bitmapped File Formats GIF PNG PSD PCX TIF JPG BMP PIC

7. Graphic File Formats TIF Format • Tagged Image File format. • Standard between MAC and PC bitmap graphics. • Handles multiple channel files. • i.e. RGB • i.e. Alpha Channels

8. Graphic File Formats TIF Format (cont.) • Writes a "header" that tells software what information is contained. • Header may increase file size. • - Not really a problem with modern hardware • Uses a LZW compression scheme. • Loseless - No data lost, just compressed.

9. Graphic File Formats JPG (Jpeg) Format • Joint Photographic Experts Group • A file format and compression scheme • Emerging as a standard format for photos • Internet use • “Lossy” compression • Reduces data during save • Data loss can be controlled • Can reduce file size in a ratio between 10:1 and 20:1

10. Graphic File Formats BMP Format • Microsoft native file format • PC system compatible • DOS • Windows • OS/2 • No MAC compatibility • Photoshop encodes to 1, 4, 8, 24 bit color but .bmp can not support channels • No file space savings for photos with .bmp

11. Graphic File Formats PIC (Pict) Format • A MAC native file format • Not PC operating system compatible • Can do 24 bit color plus an extra 8 bits • Any MAC monitor can display 32 bit PICT files • MAC system format used to exchange data via clipboard

12. Graphic File Formats GIF Format • Graphics Interchange Format • Created by Compuserve to speed downloading of graphics • Limited to 256 colors • Compression format • Can be both interlaced and non-interlaced

13. Graphic File Formats PNG Format • Portable Network Graphics • New format targeted for Internet use • Can support up to 48-bit color • 8-bit = 2^8 = 256 • 48-bit = 2^48 = 281.474.976.710.656 • trillion billion million thousand • Big compression factor • Can support multiple transparent colors

14. Graphic File Formats PSD Format • Photoshop native file format • Supports all image types from line art to photos • Increasing compatibility with other software • PSD can hold an infinite amount of channels! • Each layer can hold 24 channels • Infinite amount of layers are possible • Subject to available RAM!!!!

15. Graphic File Formats Multi-Channel to .GIF

16. Graphic File Formats PCX Format • From ZSoft Corp • Many versions exist • Great for indexed, grayscale and line art • Supports only one channel • Photoshop only supports PCX version 5! • Convert .pcx to RGB to use most Photoshop tools • PC Paintbrush format

17. Graphic File Formats Kodak Photo CD - PCD • Kodak format for images stored on Kodak Photo CD • Uses YCC color model • Limited to five image sizes • Photoshop opens as a LAB color model • Photoshop can not save as a PhotoCD format

18. Graphic File Formats Vector Formats • Vector Formats are basically defined by shapes and lines • No more than 256 colors • Clip Art • Not resolution dependent • Infinitely scalable • Not appropriate for photo realistic • images

19. Graphic File Formats Common Vector File Formats • WMF • AI • Post Script • CGM • Fonts • DRW • CIL

20. Graphic File Formats PostScript Format • Developed by Adobe Systems for typefaces • Expanded for many graphic elements • Encapsulated Post Script (.eps) is of this format

21. Graphic File Formats PostScript Format • Adobe Acrobat file format • Portable Document Format • Integrates color, graphics and text • Searchable format

22. Graphic File Formats Software Choices • Traditionally, different software creates either bitmapped or vector art • This is changing!

23. Graphic File Formats Software Choices • For bitmapped, names that include the words “Paint” or “Photo” indicates that the primary function of the software is to create and manipulate bitmapped formats • Examples • Adobe Photoshop • Deluxe Paint • Photoshop Elements • Adobe Fireworks • Corel Photo-Paint • Paint Shop Pro

24. Graphic File Formats Software Choices (cont.) • For vector art, names that include the words “Draw” or “Illustrator” indicates that the primary function of the software is to create and manipulate bitmapped formats • Examples • Adobe Illustrator • Corel DRAW • Microsoft Draw • AdobeFreehand • Serif DrawPlus • Adobe Flash

25. Graphic File Formats When to Use What and When!?!? What are the requirements of your output device?

26. Graphic File Formats When to Use What and When!?!? Image Quality File Size

27. Graphic File Formats When to Use What and When!?!? Photo Image Image Quality File Size Illustration

28. Graphic File Formats When to Use What and When!?!? Internet Photo Image Image Quality File Size Other Computer Devices Illustration