Hints and Suggestions for Using the Cancel Extractor

The cancel extractor uses a low resolution analysis of the color content of an area selected to represent the colors to be removed from the image. First open an image by clicking the "Browse" button and selecting an image on your computer. This image formats accepted by the program may be browser dependent. PNG (Portable Network Graphics format) and JPG (or JPEG, Joint Photographic Experts Group format) files are good choices. PNG has the additional advantage of file compression without loss of resolution.

Next, select an area of the image containing colors to be removed. This should not include the cancel. Simply drag the mouse over an area of colors to be removed and click on the "Use Selected Area" button. The extracted cancel will appear to the right. You can adjust the size of selected colors for removal by dragging the handles on the rectangular area with the mouse. You can also click somewhere in the area and use the mouse to move the entire area. After making any adjustments to this area, you can simply re-click on the "Use Selected Area" button to see the changes.

Click on the "Save" button to save a copy of the extracted cancel image to your computer. Depending upon your browser choice, you will either be asked name the saved file and designate the destination on your computer, or the file will download directly to your "Download" directory and be named automatically. The program saves files only in the lossless PNG format.

The cancel extractor will not work well with cancel colors that are too close to the color of the stamp. For example, a black cancel on a black stamp will not survive the removal of black from the image. For hand stamped cancels in which thin ink is used, the actual colors in the cancel will be darkened shades of the original cancel color. A suggested way to experiment with the cancel extractor is to compare the results using a lighter range of colors with a darker range of stamp colors. Often the lighter range of color will help better preserve the cancel, but with the trade-off of more stamp color remaining.

Sometimes it can be advantageous with more difficult cancel extractions (cancel close in color to the stamp) or situations with multiple colors for removal (multiple stamps of different colors, a different envelope color, etc.), to remove colors sequentially. This is easily done by removing a limited range of color that well maintains the cancel, and then saving the result. Then by browsing to this saved file, it can be opened and the extraction process continued with additional color selections in this manner. In many cases, a somewhat weak cancel on a multicolored background can be nicely extracted by a sequence of color removals starting with lighter color ranges, and then experimenting with selections of the darker colors remaining.