Getting started : Stamp Images from the Web
In order to start using the Stamp Analyser, you will need images of the stamps that you want to analyse.
There are three ways of obtaining the images.
- Scan your stamps; simple and by far the best method, click here for the procedure;
- Photograph your stamps; tricky but doable, click here for the procedure;
- Obtain the stamp images from any website, see below
You can use Safari to copy and save images directly to your photo library, and then analyze them just as you would scanned images.
On a Mac, you can also drag and drop images straight from a web page into the Stamp Analyser. When doing this, try to select an image size that appears crisp and detailed. In most cases, clicking or double-clicking the image on the website will open a larger version. Extremely large images, however, may produce poor results because they contain many interpolated pixels.
Keep in mind that most web images have a default DPI value of 72, which does not reflect the DPI at which the original stamp was scanned. For accurate perforation and frame measurements, the true scanning DPI must be known. If the DPI is unknown, these measurements will be inaccurate.
The centering calculation, however, is not affected, since it is based on relative proportions and does not depend on DPI.
This site http://www.dpiphoto.eu/dpi.htm has a good description of DPI.