In the early days of film photography capturing light accurately was a very tricky business and therefore the skies in many original vintage landscape photographs are always overexposed.
Photographers had to take a separate image of the sky and add it to the photograph during processing, which was time consuming and expensive.
In other words, clouds in photographs were a luxury item back then and most photographs didn't have any or had the same ones as other photographs.
The situation was so bad that some photography studios had negatives of the same clouds that they generously slapped onto different photographs claiming total authenticity, resulting in awkward family gatherings.
So to accurately capture the essence of photos from the early days of photography, the skies must be overexposed: no clouds for anyone!
There's no need for any fancy cloud detection algorithms because it can all be done with colour.
Here's a shot of some boisterous clouds at the Buzludzha peak that I took earlier this year.
If I simply crank up the exposure levels in some fancy photo editing software and then desaturate, I am still left with clouds.
If I crank up the brightness, then cautiously turn down the contrast, and finally desaturate the whole image, I achieve this
And finally, if tint it slightly, then I can turn any modern digital landscape photo into a believable vintage photograph, no special effects required.