jeff, welcome to RetouchPRO.
i did a little to your image yesterday but my internet was being screwy, so didnt post anything.
mainly, what you want is contrast and heighten type tools and filters. things like curves, levels, contrast/brighten, clarify, histogram adjustment and so on will bring out the detail more. but it can ONLY bring out detail where contrast currently exists. blown out whites or blacks have zero contrast so there is nothing to compare against to heighten a detail.
there is actually a fair amount of stuff in the picture. i can see two cars, a baby and a house that arent real evident in the original. or, at least i can see parts of these. and that's enough to do some reconstruction. and that's going to be the trick on your image, reconstruction.
the cars are quite old, circa 1940/1950, i'd guess. the house appears to be a wood slat type structure, two story.
the way i'd approach this is to restore first then reconstruct. get all the detail you can from what's there and clean that part up, then work on the other as desired. your main focus is there, the people. the rest is secondary and not even necessary for a normal restoration.
for the reconstruction, i'd be very tempted to completely replace the house with something similar or 'plain manilla envelope' type background. if you want to try to reconstruct it, then the best is if you can find any other pictures that that house is in and borrow data from that.
on the cars, there is probably enough data there that you could tell make and model type and find similar pictures of those and reconstruct from those. the trick would be in finding the right angles and relative positions and sizes. but, it could probably be done with enough research and work.
you've got a good large image to work with but i did notice one thing about your image that is not optimal and it may only be because of the file size restrictions here. you have an image that is 'blocked'. i used to call it 'sharpening blocks' and i think others may call it 'compression blocks' or 'jpeg blocks'. but whatever you call it, when you zoom in on the image you'll see what i mean. the image is now composed of small square blocks of varying shades and patterns. i dont know if this was done by your scanner, compressing the file to fit here on RetouchPRO, or by something else, but it's non-optimal to restoring. the first thing i did was to run my 'jgp artifact removal tool' on the image. this basically undoes the blocks and makes for a more smooth looking image.... in most cases
so, you've got a two-parter here, restore and reconstruct. the arm is easy. just clone or paint the missing part back in. the baby actually worries me more than the arm; it's very faded. the background is optional. replace with similar, reconstruct by guesswork, or leave it completely alone and let the viewer fill in the details. it's up to you
