The Truth About Airships, Towers & Domes.

Almost all of the photographs from the 1800s seem to have the sky purposely doctored to blur it out. Notice how you can never see any clouds, distant hills or land on the horizon? Even the sun.
And on some of them, you can even see the sloppy pixelated cuts around the buildings.
Are they purposely hiding something?
And if so, What & Why?