What is the best practice to build a mosaic for scanned hardcopies when there are varieties in the backgrounds colors, some have dark backgrounds and the others have white backgrounds?
For more details:
If the major of the added rasters have white backgrounds, the rasters with dark backgrounds appear in white color region, and if the major of the added rasters have dark backgrounds, the rasters with white backgrounds appear in black color region!
Note that these varieties come from the origin of the scanned hardcopies since these are from different sources and maybe drawn on different papers!
What might be the issue here?