SCANNING

The first step in the examination of an overprint is to obtain a digital image of the overprint. Two ways of accomplishing this are the use of a digital camera or the use of a flat bed scanner. Of the two methods, the use of a flat bed scanner is by far the less complicated. An excellent review on scanning is available on the Internet - http://www.scantips.com/basics01.html . The two major uses of scanned images are for print or for display on the computer monitor. I will be only demonstrating the uses for monitor displays.

The scanner that I am using is a Canon CanoScan LiDE 35. The scan bed size is 8 1/2 x 11 inch. This is a junior member of the Canon scanner family and is available - with rebate - for $50. A scan is initiated in PSE3 by clicking on File, then clicking on Import on the submenu and then clicking on CanoScan on the new submenu. The scan menu that is displayed on the screen is reproduced in Fig. 2.


Fig. 2

On the Scanner Menu, click on Settings and then click on Preferences. The Preferences Menu will be displayed on the screen. The preferences that I use are shown in Fig. 3.


Fig. 3

A scan is initiated by placing the item on the scanbed and closing the lid. Click on Preview (Scanner Menu). The preview process can be stopped by depressing the ESC key on the keyboard. Position the crosshairs at one edge of the area you wish to have scanned and drag the dotted box to define that area. Click on Zoom (Scanner Menu). By placing the crosshairs on one of the sides of the dotted rectangle, the crosshair is replaced by a double headed arrow and the dotted line can be dragged to better define the area to be scanned. This process can be repeated for the other 3 sides.

On the Scanner Menu, click on Main and set the scan parameters. For this example, the settings that I have chosen are Color Mode: Color (Photo) and a Resolution of 600dpi. Click on Scan (Scanner Menu). The process is displayed in Fig. 4.


Fig. 4

The Resolution value set for a scan depends upon the intended use of the scan. The normal screen resolution is 72 pixels/inch and a scan resolution of 72 dpi will generate an image equal in size to the original object. A scan resolution of 720 dpi will generate an image 10 x 10 or 100 times the area of the original. Of course the file size is also much larger. The choice of the value of resolution to be used is an individual choice. For the study of the Krakow overprints, I have chosen 600dpi.