Multimedia Specification Design and Production 2012 / Semester 1 / L4 Lecturer: Dr. Nikos Gazepidis

2 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 Graphic File Formats

3 Native File Format Graphic File Formats

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

6 Common Bitmapped File Formats Graphic File Formats 1.TIF 2.JPG 3.BMP 4.PIC 5.GIF 6.PNG 7.PSD 8.PCX

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

8 TIF Format (cont.) Graphic File Formats  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 JPG (Jpeg) Format Graphic File Formats  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 BMP Format Graphic File Formats  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 PIC (Pict) Format Graphic File Formats  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 GIF Format Graphic File Formats  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 PNG Format Graphic File Formats  Portable Network Graphics  New format targeted for Internet use  Can support up to 48-bit color 8-bit = 2^8 = bit = 2^48 = trillion billion million thousand  Big compression factor  Can support multiple transparent colors

14 PSD Format Graphic File Formats  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 Multi-Channel to.GIF Graphic File Formats

16 PCX Format Graphic File Formats  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 Kodak Photo CD - PCD Graphic File Formats  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 Vector Formats Graphic File 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 Common Vector File Formats Graphic File Formats WMF AI Post Script CGM Fonts DRW CIL

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

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

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

23 Software Choices Graphic File Formats Examples Adobe Photoshop Deluxe Paint Photoshop Elements Adobe Fireworks Corel Photo-Paint Paint Shop Pro  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

24 Software Choices (cont.) Graphic File Formats Examples Adobe Illustrator Corel DRAW Microsoft Draw AdobeFreehand Serif DrawPlus Adobe Flash  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

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

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

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

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