LL, well, that added a lot of mood. i wouldnt go overboard on that. i'd erase a bit of the dark of that sky (you do have it on a separate layer, right?). it's very good work, but it significantly changes the look of the image. it's fine if that's what you or the customer wants, of course. but in restorations, it's a good idea to keep things looking pretty much like the original. the sky was bare and flat, so i do like that you added a bit, but you've now got it as a darkening, gloomy sky sort of image and that just changes it a bit much. make sense?
as for layers, think glass. each layer is like a blank piece of glass, completely transparent at heart. and each layer stacks on top of the next. so, if you were looking down from the top through the rest, like glass, you would see down through the layers, providing there was nothing on the various panes of glass. that's the simplicity of it. every layer is like that.
but, where it gets a bit more complex is, some of the 'glass' you stack up has something on it. you can put whole separate images on top of other images this way but you're only going to see the one on top, or, the one that is highlighted if you have one other than the top one highlighted. but, it's always the same rule even if you have one down in the middle highlilghted. EVERY layer below that one is in the stack. by highlighting you are simply putting yourself right over that piece of glass, instead of the one that is actually on top. with me so far?
'adjustment layers' are specialized layers. but, they still follow the same rule. things like 'levels', 'curves', and 'hue/saturation' can be adjustment layers. they 'adjust' the 'glass' below them based on what they do. the closer the lower layers are to the top, beneath the adjustment layer, the more influence the adjustment layer has on it.
ok, there's still a bit more to layers, but i'll let you play with that for a while
