Eliminating the background shadow from a scan can be problematic for pen and ink on paper illustrations. Often a light gray background appears in the final web image of a scanned pen and ink illustration.
The pen and ink illustration on the left was scanned in with a portable scanner. The image was placed in Google's Picasa editor which, to date, doesn't appear to have a transparent gif tool. However, it does have a good cropping tool and a light tool. Still though, after numerous efforts to remove the gray color cast from the scan, the gray color cast remained(for color photos, Picasa's color cast tool has been demonstrated to be helpful for removing blue color cast but this is done by adding orange. ).
For black and white color cast problems, which results in a gray color cast, it doesn't appear that Google's Picasa's tool has an easy solution.
After a little searching, BookMarkTutoring.com found an online image editor at http://www.online-image-editor.com/ to create a transparent gif from uploaded files. The transparency option at online image editor removed the color cast as can be seen from in the pen and ink illustration above.
The gray colorcast can also be removed with Microsoft Word's built in picture editing tools. And Word's Art tools can be used to create a transparent gif, and hence remove gray colorcast, but Word's art tools tend to remove details. BookMark is still investigating which tool is better for keeping details. However, so far on a cost basis, online image editor appears to be the low cost solution to removing colorcast and removing it when desktop software tools are not available.
Next on BookMark's list is investigating line smoothing capabilities for different graphic design software tools.
