I'm not sure if this will work, but this is how I would do it. First, I would open the file in Photoshop. Then, I would create a new layer on top of it. I'd use the same pen color to draw over the image in the new layer. Then, just delete the original layer (the original image).
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The Queen of DaniWeb
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since Feb 2002
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It didn't work well for me. 
