>Hi Al.
>I'm using an OCR DLL to extract the text from an images.
>The text in these images are always black. The black color is only used in the text part.
>So, to improve the OCR results, I need to remove all non black pixels or change them to white, and save this "new image".


I would suggest saving the image to a disk file, and manually manipulating it in a software program like GIMP to learn how to adjust it to your specifications, and then automating that process from the command line as per a script for future automated use.