1. Basic Digital Imaging For PE 266 Technology in HPER

2. 2 Types of Computer Graphics • Raster Graphics - also known as Pixel-based (you “paint” with pixels) • Building blocks of images are pixels • Pixels are tiny squares • AKA “painted” images or bitmapped images • Cameras and scanners capture images in pixels • Vector Based (you “draw” objects with vectors) • AKA “drawn” or “object-based” images • Images are “described” in mathematical terms

3. Comparison of image types • If you zoom in close on a pixel based image you will be able to see the pixels (you will see jagged edges when you zoom in closely) • If you zoom in close on a vector based image you will always see smoothly drawn edges regardless of how closely you zoom in

4. Comparison of image types • Pixel based images can be edited one pixel at a time – individual pixels can be edited • Vector based images are edited as a whole object – you can’t erase part of a vector image

5. Comparison of image types • Pixel based images are typically used for photo-type images (from cameras and/or scanners) • File sizes tend to be larger than vector based images • File types are things like jpg, gif, bmp, & tiff • Vector based images are usually used for line art and web pages • File sizes tend to be smaller than pixel based images • Flash files are vector based • Vector images can be scaled to any size with no loss of image quality

6. Issues when capturing images • One of the main issues is resolution • Resolution is the number of pixels (usually expressed as width and height) • More pixels means better quality (and larger size), but it also means larger file sizes • Larger file sizes mean it will take longer to work with and also to display on a web page

7. More on resolution • Images are always captured in pixels per inch although it is often mislabeled as dots per inch (or DPI) • DPI is actually used to describe the resolution for outputting images – normally to a printer

8. Guidelines • Always capture images in higher resolution than you ultimately will need (if possible). • After capturing images process them to get the desired final image

9. Basic image processing • Archive your original image (as raw, tif, or png file) and work on a copy. • First crop your image • Then size and if necessary re-sample your image • Adjust levels • Compress and export image

10. Digital Imaging Assignment • Acquire 2 images – one from a camera and one from a scanner • Process/optimize both images for web page • Create graphic with Fireworks and export it as a gif

11. Turn in the following: • 3 files should be turned in (and the file names should identify which is which) • Both processed images – one from camera and one from a scanner (.jpg) • Gif file created in Fireworks • Assignment can be turned in through e-mail or on USB storage device