Multimedia Specification Design and Production

2012 / Semester 1 / L4Lecturer: Dr. Nikos Gazepidisgazepidis@ist.edu.gr

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

A usable description of any software's proprietary file format.

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 = 256 48-bit = 2^48 = 281.474.976.710.656

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

Photoshop RGB

Indexed 256

.GIF

Convert to:

Save as:

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 realisticimages

19

Common Vector File Formats

Graphic File Formats

WMFAIPost ScriptCGM

FontsDRWCIL

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

ExamplesAdobe PhotoshopDeluxe PaintPhotoshop ElementsAdobe FireworksCorel Photo-PaintPaint 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

ExamplesAdobe Illustrator Corel DRAWMicrosoft DrawAdobeFreehandSerif DrawPlusAdobe 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 Quality File Size

27

When to Use What and When!?!?

Graphic File Formats

Image Quality File Size

Photo Image

Illustration

28

When to Use What and When!?!?

Graphic File Formats

Image Quality File Size

Photo Image

Illustration

Internet

Other ComputerDevices