Graphics Tutorial

There are two types of computer graphics:
VECTOR BITMAP (raster)
Exist as a mathematical equation.
Mathematically defined lines and curves. 		They are rectangular grids made of little
squares (like checkerboards).
Is resolution independent
- scaling want effect image quality.		 When a bitmap picture is resized,
it often distorts the image.
Vector art consists of fills and outlines applied
to a geometric description of a wireframe design.		 The grid of pixels. Has four basic characteristics
dimension, revolution, bit depth, and color model.
Characterized by geometric precision
and a perfect focus. 		Bitmapped image can simulate photographs
and paintings because qualities of lighting
transparency and depth of field.
Because computer screens are made up of a grid of pixels,
both vector and pixel images are displayed as pixels.

filename extension - the portion of a filename, following the final point,
which indicates the kind of data stored in the file.

 

GRAPHIC FILE FORMATS
PCX, BMP PCX and BMP are bit-mapped file formats created by paint programs, like PC Paintbrush or some screen-capture programs. PCX is one of the oldest and
most common bitmap formats available.

PDF

 (PDF - Portable Document Format). The native file format for Adobe Systems' Acrobat.  PDF is the file format for representing documents in a manner that is independent of the original application software, hardware, and operating system used to create those documents.  A PDF file can describe documents containing any combination of text, graphics, and images
in a device-independent and resolution independent format. These documents can be one page or thousands of pages, very simple or extremely complex with a rich use of fonts, graphics, color and images.
DRW DRW files are vector graphics created by Micrografx Designer.

GIF

 GIF (Graphics Interchange format) is a file format established by CompuServe.  A GIF file (Usually 256-color) is a bitmapped file.
The GIF89a lets you specify the appearance of transparent areas in the image.  In Photoshop choose File > Export, and select an export format or method from the submenu.

JPEG

 A JPG file (Joint Photographic Experts Group) is a specially compressed file in bitmapped format. The file size of a JPG file is much smaller than similar pictures in other formats.

PCD

 PCD is a Kodak Photo CD file in bitmapped format. A PCD file actually contains five different resolution (ranging from low to high) of a slide or film negative.

EPS

 EPS stands for Encapsulated PostScript. This is a postscript description of an image for printing purposes. A TIFF header is added to an EPS file so that it can be viewed.

TIFF

 TIF stands for Tagged Image File Format. Files with the .TIF extension are usually created by scanners or image processing programs. These bitmapped files come in a number of different classes. There are many different varieties of TIFF.

TGA
(targa)

 (TGA - The Truevision Targa Graphics Adaptor file format). The TGA format is a common bitmap file format for storage of 24-bit images. It supports colourmaps, alpha channels, compression and comments.

WMF

 WMF stands for Windows MetaFile. This native Windows vector format is used by the Windows Clipboard.
FLM The Filmstrip format is used for animation or movie files created by Adobe Premiere.  When editing a Filmstrip file in Adobe Photoshop, you must not resize or crop if you plan to export the image back into Adobe Premiere.
FlashPix Live Picture Inc., Eastman Kodak Company, Microsoft Corporation, and Hewlett-Packard Company joined in unveiling a new imaging architecture and image file format, "FlashPix."  Targeted primarily for the consumer market, FlashPix is designed to simplify and expedite image processing on computers and networks.

For example, the user will no longer have to calculate the necessary image resolution to achieve the best output from a digital file. FlashPix will make a determination based on communications between the scanner, imaging software, and printer. These functions will take place in the background without the user realizing they're taking place.

Kodak provided advanced filtering algorithms and color space transformation technology.  FlashPix supports two different color space options - a calibrated RGB color space definition and Photo YCC, the color format used with Kodak Photo CD. FlashPix also includes Microsoft's OLE Structured Storage and highly optimized JPEG encoding software from Hewlett-Packard.

PNG
(ping)		 Like GIF, PNG (portable network graphic) offers lossless compression (it doesn't actually discard image data) and indexed color.  Unlike GIF, it also supports full 24-bit color just as JPEG does. And these features make PNG a standout:  built-in gamma, alpha-channel transparency, and two-dimensional interlacing.

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DATA TYPE FILE FORMATS
BLACK & WHITE BMP, EPS, GIF, ICO, IFF, IMG, MAC, MSP, PCX, PSD, RAS, TIF, CLP, WMF
GRAYSCALE EPS, JPG, PCX, PSD, PXR, RAS, SCT,TGA, TIF
INDEXED 16-COLOR BMP, GIF, ICO, IMG, PCX, RAS, RLE, TIF, CLP, WMF
INDEXED 256COLOR BMP, GIF, IFF, PCX, PSD, RAS, RLE, TGA, TIF,CLP, WMF
RGB HiCOLOR BMP, TGA
GRB TRUE COLOR BMP, EPS, IFF, JPG, PCX, PSD, PXR, RAS, TGA, TIF, CLP, WMF

Notice that GIF for example exists only in indexed color

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DATA TYPE FILE FORMATS
IMAGES BMP, CLP, CUR, DCS,EPS, GIF, ICO, IFF, IMG, JPG, MAC, MSP,
PCD, PCT, PCX, PSD, PXR, RAS, RLE, SCT, TGA, TIF, WMF
GRAPHICS CGM, CLP, DRW, DXF, HGL, PCT, PIC, WMF, WPG
ANIMATION FLC, FLI, FLX
VIDEO AVI, MOV, MPG
AUDIO MID, RMI, VOC, WAV, MP3
INTERNET IMAGES GIF, JPG, PNG
OTHERS DBF, DOC, PPT, RTF, CDR

 

R E S O L U T I O N
Resolution is the number of dots available
to represent graphic detail in a given area:
on a computer screen the number of pixels per linear inch - ppi
(72 to 96 ppi is the maximum a monitor displays)
on a printer the number of dots printed in a linear inch - dpi
on a scanner the number of pixels sampled per linear inch of the scanned image- ppi
IMAGE RESOLUTION is measured in pixels per inch - ppi
PRINTER RESOLUTION is measured in dots per inch - dpi
HALFTONE FREQUENCY which determines the size of printed dots is measured in lines per inch - lpi
If an image has a resolution of 72 ppi, this means it contains 5184 pixels in a square inch
(72 pixels wide x 72 pixels high = 5184).
Because the number of pixels in an image is fixed, when resolution decreases, the image size increases.
Conversely, if we increase the resolution of an image, the image size (dimension) will decrease.
Higher resolutions allow for more detail and subtle color transitions in an image.

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FILE SIZE
File size (kilobytes) = (resolution to square power) x With x Height x Bits 8,192
8.192 is the number of bits in a kilobyte
File format can also affect the file size of bitmapped image file.  eg. EPS file typically includes a preview image, TIFF files often include built-in compression. Also binary-encoded bitmaps are half the size of ASCII-encoded bitmaps.