Presentation on theme: "Introduction to Computer Graphics Raster Vs. Vector COMMUNICATION TECHNOLOGY."— Presentation transcript:
Introduction to Computer Graphics Raster Vs. Vector COMMUNICATION TECHNOLOGY
Intro to Computer Graphics Computers have radically changed how graphics, photos and printed materials are produced. What once took a highly trained artist many hours to produce with specialized equipment can now be done much easier using computer software.
Raster Graphics (write blue text) Graphics are produced using a grid of small squares known as pixels. Each pixel is assigned a specific colour value and location. When editing a raster graphics (ex. Digital photo), you are actually editing pixels rather than objects or shapes (Photoshop) Pixels can be seen by zooming in on a digital image (tiny squares).
Raster Graphics (write blue text) Raster graphics are generally larger files than vector images. Images lose quality (become “ pixelated ”) if enlarged more than 20% of the original size.
Vector Graphics (write blue text) Drawing programs such as CorelDraw and Adobe Illustrator produce vector graphics. These types of graphics are made of lines and curves defined by mathematical objects called vectors ( geometric characteristics).
Vector Graphics (write blue text) A vector graphic can be moved or resized without losing quality and file sizes are generally smaller than raster graphics. Best choice for creating type or logos where crisp outlines are needed since clarity is not lost when scaled/resized.
Common Image Files (write blue text) BMP: Bitmap is the standard Windows image format GIF: Graphics Interchange Format; designed to minimize file size and download (electronic transfer) time
Common Image Files (write blue text) JPEG: Joint Photographic Experts Group; compresses file size by selectively discarding data, unlike GIF format, JPEG retains colour information. TIFF: Tagged-Image File Format ; used to exchange files between applications and computer platforms ; “flexible” bitmap image supported by virtually all paint, image editing, and page-layout applications.
Resolution (write blue text) Resolution is how many pixels or dots make up the image you see. On a monitor, resolution is measured in pixels per inch. Screen resolution is 72 ppi.
Resolution (write blue text) Print resolution is measured in dots per inch. Print resolution should be at least 150 dpi. For high quality printing, images should be 300 dpi or greater. Print resolution depends on the printing press being used (Offset, Web etc.).