| Tech Lit | CD-R | Scanning | WordPad | Movie Maker |
Let's discuss for a moment what you'd like to do? Do you want to get a picture, photograph, or diagram into your computer? What about a sketch? Do you want to get a page of text into your computer without having to retype it? Can you make an enlarged print from a negative? Yes, yes, yes.
| depth: | 16-bit color | 8-bit color | 4-bit color | 3-bit color | 2-bit color | 1-bit color | 1-bit color | |
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| size: | 15,606 bits | 6,262 bits | 2,710 bits | 2,710 bits | 2,710 bits | 2,710 bits | 2,710 bits |
Notice that the image appears close to a 1" square if you're using a typical PC monitor set to display 680x480 pixels. (Pixels = Picture elements are the tiny squares that form the image on screen.) What if your screen resolution is set at 800x600? 1024x768?
| 65x65 pixels @ 75ppi. | Magnified 4X. You can begin to see the pixels. |
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| Click to magnify to 8X. |
The actual screen size of digital images depends upon the size and display settings of the monitor on which they're viewed. E.g., a 72 pixel square would appear 1.14" in height on a 12.75" x 9.5" (W x H) display set at 800 x 600 pixels (9.5" x 72 pixels ÷ 600 pixels = 1.14"). The square would be physically smaller on the same screen if the screen resolution is set higher, say at 1024x768 pixels.
Before you scan your photos or take digital pictures for use on the web, you can set the resolution to about 75-100 ppi (pixels or dots per inch). This way your photos will be approximately the same size as your originals. E.g., a 3.5"x5" photo would appear approximately as if you held the photo up to your screen. Most computer setups display at around 75ppi. E.g., a 12" wide monitor set at 800 pixels displays about 67 ppi (800 pixels ÷ 12" = 66 2/3 ppi). The actual ppi screen resolution varies quite a bit depending upon the size of your monitor and your graphics card settings.
Higher resolutions are really only useful if you are going to print or enlarge your photo. Higher resolution images will often appear too large on the computer monitor. To find out how your images will appear on screen, take the original dimensions and multiply by the resolution.
original dimensions (inches) * resolution (ppi) = onscreen dimensions (pixels)
For example if you have a 3x5" photo that you'd like to scan so that it will be 150 pixels wide onscreen, take 3R = 150 and solve for R. R = 50, so you could scan your photo at 50 ppi and get the desired results.
Another consideration, of course, is file size. Probably most photos shouldn't exceed about 40KB since this would take over 10 seconds to download over a 28.8Kbit/sec modem connection. The way to keep your file size small is to limit resolution, and even color depth. Compressed file formats are very helpful.
JPG (Joint Photographers Experts Group) is usually the best format for web photographs. GIF is better for graphic images, drawings, diagrams, graphs, etc. where there are some straight lines or geometric shapes, and less than 256 colors.
| Tech Lit | CD-R | Scanning | WordPad | Movie Maker |
Alternative Learning Division
Copyright © 2007
MATC.
Revised:
March 05, 2007
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