Hello! I find myself without an answer to something, and although I shoot a Hassy 500c/m with T* lenses, I knew that this group of photographers would know more than my own.

I don't understand how many older landscape photographs have the depth of softening tonality into the distant background, even without loss of clarity. It seems fairly common before 1950, and decidedly less so afterwards. For examples of what I mean, I'll turn to Adams due to the availability of his works:

Mount Clarence King, 1925

Juniper Trees, Crags Under Mount Clark, 1936

Mirror Lake, Mount Watkins, Spring, 1935

Mount Moran, Autumn, 1948

Obviously, shooting near water and in the desert can present a lot of haze, but in the mountains this frequently isn't the case. Is this effect strictly atmospheric? I was wondering if uncoated lenses, or perhaps older, more blue or red light sensitive film had anything to do with it?

Many of my favorite works have this pleasing, layered appearance, but it's something I never seem to be able to create myself, regardless of film or filtration used. Any advice would be more than welcome.

Thanks!