Digital Imaging Raster (Bitmapped) Images

1. How they work…  Image data is stored in literal “map”  Each pixel (picture element) is measured for its level of red-green-blue light  Can be painted, scanned, or photographed with a digital camera

2. Painting  Common tools used to create images  Beginner Level  MS Paint, ClarisWorks  Intermediate  Graphic Converter, L-View Pro  Advanced  Adobe Photoshop, PaintShop Pro

3. Digital Cameras  Operate similar to a standard camera  Use a CCD (charged coupling device) to measure light (RGB values)  Quality depends upon resolution (pixels per inch) that the camera can capture  Hint: Monitor can only display 72DPI, so if primary target is screen…

4. Scanners  Operate similar to digital cameras (use CCD), but are capably of much higher resolutions  Even the most affordable scanner ($150) is capable of capturing images at qualities better than the best desktop printers  Look for price, speed, and bundled software in a new scanner

5. Manipulating Images  Real power of computers is to correct/edit images  Basic paint tools edit on a pixel by pixel basis  More powerful software includes more powerful tools…  Photoshop: Selections, Layers, Filters

6. Manipulating (cont.) Selections  Selection tools allow you to choose only specific areas of an image  Once isolated, those areas can be affected without touching others  Photoshop includes complex selection tools

6. Manipulating (cont.) Layers  Layers allow further flexibility by isolating whole sections from each other  Act like sheets of overhead transparencies  Can be hidden, created, discarded as needed

7. Manipulating (cont.) Filters  Also called “plug-ins” for Photoshop  Pre-defined special effects for images  Make professional effects easy to achieve

8. Saving and Using Images  Virtually all applications can import/use raster images  Common formats:.BMP, PICT,.GIF,.JPG,.TIF

9. Saving/Using Images (cont.)  MS Word: supports GIF, BMP, JPG, TIF  Claris/Appleworks: supports GIF, BMP, JPG, TIF, PICT  FileMaker: supports GIF, BMP, JPG, TIF, PICT

10. Image File Types  BMP and PICT: Standard types for PCs/Macs. Up to 16 million colours, uncompressed  GIF: max 256 colours, can be transparent, animated, colour-by- numbers compression. Used for web buttons!  JPG: “lossy” compression for full-colour photos. Best for on screen use, Internet.  TIF: “lossless” compression for photos. Hold unlimited colours and DPI for professional printing