Here is another of those great old large-format photos from Detroit Photographic Company, showing crewmen of the battleship USS Iowa standing by a forward 12-inch gun turret, c. 1897. I've attached before&after editing shots, and a work-in-progress screen capture, made while I was cleaning up the selection that was created from a channel mask. You can get a pretty good idea of what condition the photo was in when I started working on it by taking a close look at the gun tubes as they appear in the screen cap. Nearly every picture I've selected to restore from the LOC is riddled with that kind of stuff (or worse). And the sky almost always has no cloud formations; in 1897 the sky was washed-out but at least appeared clean & white in the finished photo. After 117 years, the sky looks more like a dirty gym sock. There's no point in trying to clean it up, the only practical option is to replace it, which is where the channel mask comes in. It's the best way to delete the whole sky and still preserve everything else, which then is fixed using cloning, healing brush, filters, etc. Critique is welcome and appreciated.