Basic Digital Imaging For PE 266 Technology in HPER

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

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

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

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

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

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

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

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

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

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 or on USB storage device