Basics on scanning and resolution

This is not a 'how to' document but rather a guide to selecting the most appropriate resolution for a scanning project.

Before scanning:

• To determine resolution, think about the purpose of the final image and the type of work to be scanned.
• Do you want the image larger or smaller than the original, or same size.
• Determine the scale by dividing the required size by the original image.
• Bear in mind that resolution and size are inversely related.
• Commonly choosen formats: JPEG, TIFF, GIF, BitMap
• Note that a scanning at high resolution eats a lot of space and is not necessarily better.

Scanning for display on a computer monitor

• A resolution of 75 or 100 dpi is probably sufficient
• Normally the resolution of the monitor

Line Art

Resolution should be the same resolution as the output device (printer) up to a limit of 1200 dpi. Again adjust until the quality is good enough.

Scanning in photos

To get optimum scanning resolution you need to know the line per inch (lpi) resolution of the printer.
Then determine the scanning resolution using the following
Min Scanning res = lpi * 1.5
Max Scanning res = lpi*2

Black and white images

Working in grayscale capture all full 8 bits per dot, which will give 256 shades of gray.

Color Images

These are a bit trickier than black and white photos. You want to capture 24-bit bits of data per pixel to reproduce the full spectrum of 16.7 million colors of which an RGB monitor is capable.

OCR

Try a minimum of 300 dpi and increase if its not good enough