Digital Imaging

Raster (Bitmapped) Images

1. How they work…1. How they work…

Image data is stored in literal “map”Each pixel (picture element) is measured for its level of

red-green-blue lightCan be painted, scanned, or photographed with a digital

camera

2. Painting2. Painting

Common tools used to create images

Beginner Level MS Paint, ClarisWorksIntermediate Graphic Converter, L-View ProAdvanced Adobe Photoshop, PaintShop Pro

3. Digital Cameras3. Digital Cameras

Operate similar to a standard cameraUse a CCD (charged coupling device) to measure light

(RGB values)Quality depends upon resolution (pixels per inch) that

the camera can captureHint: Monitor can only display 72DPI, so if primary target

is screen…

4. Scanners4. 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 Images5. Manipulating Images

Real power of computers is to correct/edit imagesBasic paint tools edit on a pixel by pixel basisMore powerful software includes more powerful tools…Photoshop: Selections, Layers, Filters

6. Manipulating (cont.) Selections

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

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

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

8. Saving and Using Images

Virtually all applications can import/use raster imagesCommon formats: .BMP, PICT, .GIF, .JPG, .TIF

9. Saving/Using Images (cont.)

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 Types10. 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