File formats

Question 1

TIFF

Answer 1

• Tag Image Format
• Developed by Aldus in1986
• Today is one of the most versatile, reliable, and widely supported bit mapped format. It includes a number of compression schemes and isn’t tied to any hardware.

Question 2

PICT

Answer 2

• No acronym. Is native to the Mac. Introduced in 1984. Developed by Apple-short for picture.
• Used by many applications, especially when images are designed for screen previews-not for output on printer.
• Can contain both bit-mapped and object oriented graphics.

Question 3

EPS

Answer 3

• Encapsulated PostScript
• Format for storing high resolution postscript illustrations.
• Developed by Adobe

*consists of 2 parts:
PostScript description
Bitmapped PICT preview (72 dpi)

Question 4

GIF

Answer 4

Graphics Interchange Format-

• Widely used for internet graphics-best for images composed of lines and solid blocks of color.
• Highly compressed format designed for network file transfer.
• Lossless compression to keep file sizes as small as possible.
• A GIF’s color palette is limited to a maximum of 256 colors-must already be indexed with a color resolution of 8 bits or less to save it as a GIF.
• Don’t use a GIF for gradations of color- use a JPEG.
• GIF’s also provide us with transparency(only one) and animation- JPEG can’t do either and PNG only has transparency features.
• Files define a protocol intended for the on-line transmission and interchange of raster graphic data in a way that is independent of the hardware used in their creation or display.
• Developed in 1987 by CompuServe.
• A GIF data stream is a sequence of protocol blocks and sub-blocks representing a collection of graphics.

Question 5

JPEG

Answer 5

• Joint Photographic Experts Group
• Is a standardized image compression mechanism.

*“Lossy” file format
Economizes the way data is stored
Identifies and discards extra data
When decompressed, image will NOT be identical to the original

• Files automatically decompress when opened.
• Works with color resolutions of up to millions of colors (also called 24 bit color).
• Works great on the Web for photographs and other continuous-tone images.
• Is not a file format, but rather a method of data encoding used to reduce the size of a data file.-commonly used within file formats such as JFIF and TIFF.
• Is designed for compressing either full color or grayscale images. doesn’t work well on simple line art or lettering.

Question 6

GIF

Answer 6

Graphic Interchange Format

Question 7

PNG

Answer 7

• Great for the Web for either line or continuous tone image data.
• Portable Network Graphics
• Lossless format, compressing files without losing any quality.
• PNG format was developed a few years ago to replace the older and more limited GIF file format on the web.
• Can be palette-based, grayscale, or true color images with color resolutions of up to 48 bits.
• Has cross-platform color and gamma correction and fully variable transparency (multiple transparencies-not like GIF with one) effects but no animation.
• Usually smaller than a GIF.

Question 8

Bitmapped image files

Answer 8

Stores image data as a map of individual pixels.

*GIF and JPEG are bitmapped formats

Question 9

Vector based image files

Answer 9

Stores image data as a set of mathematical formulas that instruct the computer how to draw the image.

*PNG contain both bitmapped and vector-based image data.