Remove stain that covers app 50% of color photo in cs5

Regarding Content Aware Fill:

Use the Quick Selection tool to make a Selection of the background.

Cmd+J to put it on a separate Layer

Lock the transparent part of the layer for insurance (it is the symbol adjacent to the word Lock)

Use the Lasso tool to select the stained areas.

Choose Edit > Fill ... Content Aware (Next to the word Contents)

The reason the background is placed on a separate layer its to keep Photoshop from referencing the people as it calculated the fill content.

Good luck!

Perspective Crop will square up the image

Content Aware Fill will get rid of the stain in the background

The faces require individual correction but the print is badly bleached, stained and splotchy so there is little to recover.

Woman's face needs more time than I devoted to it.

I overdid the sharpening.

Under pressure to do some chores.

I would try Curves or Selective Color for that area. Match the dark grey background and the rest of it should come close.

You Can Edit the image Channels from Channels Panel      Window> Channels  and it will be more easy if you change the color mode to CMYK from Image> mode.

You can also use the adjustment layers from Image> Adjustment .... it will give you a mask to adjust exact area and leave another.