This is a bit of a geeky aside, but I have to admit to hating the shadows that often show up on scans of certain xtabs, e.g. in Google books. Let’s consider this example (also present in the HathiTrust version (link)), of the Amsterdam (1899) final standing xtab:
The uneven background shading is so uneven that it made me wonder if Photoshop (LE – my version) could be used to clean up the scan? It can, but it took me a bit of fiddling to find it – so I’m making this post as much as a handy reminder for myself, as for others:
First step, I open the (Public Domain) document and find the right page – then I use Window’s Snipping Tool to get the above clip. If I didn’t need to save the origin to show it above, I could just use the clipboard to transfer the image:
The toolbar button of overlapping pages, circled in red, represents the clipboard copy feature. This allows PhotoShop to quickly load up the image, via the Alt-f-n-d shortcut (i.e. File -> New -> Image from Clipboard). Then select the area which needs the fixing (the more selective, if possible, the better):
OK, another necessary subtle step, is to select the Shadows (or Midtone) radio-button in the dialogue box, then use the Lighten control as many times as needed (and no more!). The slider bar setting for Saturation can also be used. Remember, Ctrl-Z is your friend, as this step can involve some trail-and-error if you over/under do the correction. The Reset Image button in the dialogue box is also useful. Here’s the result of my finagling:
An improvement, which took less time to do than to explain here!