To: Reader from Texas, US, XP, Photoshop 7.0
I have maps that I am scanning to digitize soil surveys - the maps are folded in two spaces width wise - landscape paper at size 11x17. What is the easiest way to remove the creases from a gray scale with some black outlines - and some pattern - these are aerial photos - no solid colors.
Depends on what the background looks like... here are some tips
If the "gray" in the background is uniform, then you can extract the black, raise it to a new layer, by using
* Select > Color Range set to a very low number like 1 - 8, clicking on BLACK as the 'sampled' color.
Once a suitable selection is obtained, simply raise that selection to a new layer, or use the "float" command, Ctrl/J, (Mac: Cmd/J) and raise a copy to a new layer.
Now remove offending creases and grays, replacing them with the flat gray.
Generally, if the background is "modeled" or contains various shades of gray and textures, the creases will be very difficult to remove in an automated fashion.
In this case, use the Cloning Stamp (Tap: S), the Smudge Tool (Tap: R, behind the Blur tool) and Brushes to rebuild the 'fixed' areas around the crease.
Sorry, for some retouching tasks there are no silver bullets.