Replacing skies is one of the latest fads with some of the newest software making it an effortless task, but the idea is almost as old as photography itself.
I was just going to call this blog 'Replacement Skies, but that was too boring and the current title a more accurate description of many of the examples to be seen. And to be fair I'm sure more likely to grab your attention.
Skies in photographs have always been altered and changed but it's so much easier with the latest software. In Victorian times using glass plates a characterful sky could be added t make a flat landscape look more dramatic by multiple printing or sandwiching two plates together. With film sandwiching two negatives together would give a result. This was much easier with black and white as you could work under safelight conditions while perfecting your composition, but was possible, if trickier, with colour.
It's supposed to help if foreground and sky were taken with lenses having a similar angle of view
Moving on to colour transparencies it was the sandwiching technique that was used. Two transparencies, a landscape with a blank white sky would be sandwiched with a picture of a sky taken at a different time. The key here, because you didn't have the luxury of being able to mask or shade a sheet of printing paper was to shoot the sky image with a blank bottom part (let's say the bottom two thirds being lank if you wanted to use the 'Rule of Thirds' in your compositions). Indeed there had to be some preplanning because he frames of film needed to be properly aligned and firmly held by the mount. That said, if you had a good sky you would shoot several variations to give you more flexibility later.
Both Vulcan and explosion were taken at RAF Cosford
So how do you go about shooting a sky with a blank lower part? It's actually ether simple. Hold a piece of white card right in front of the lens and angled to catch the light. The exposure for the sky (determined beforehand without the card in place) would be such that the white card part of the image would burn out anfd be devoid of detail. The landscape area of the sandwiched slide would show through clearly. Because the card would be right close to the lens it would be out of focus and thus give a soft edge to the sky, giving a more natural looking transition.
More natural. Well that brings me to the big problem with the technique, both in the past and especially so with software. While sky replacement in software can look seamless, there are so many tell tale signs that give the game away.
Glasgow
Unless you're able to partake in intergalactic travel to a planet in a binary star system, the light on an earth landscape and sky comes from one direction only. Not only direction but quality and the presence, or lack of, shadows is important. Of course, there are times when a second light source does illuminate the subject such as a camp fie or street light but the sky and background would still be lit equally. As well as the angle of light colour needs to match too. Midday sun on the land and a sunset behind, no. It's interesting how even being slightly out does start to ring alarm bells.
Of course, if you're after a more surreal look it doesn't matter. Special effects and whacky looks are commonplace these days, and don't fool anyone. The end result has to look good and not look as though it's been thrown together, so you really have to pay attention to detail.
But talking of surreality, going back to film, you could create an amazing landscape that people would say 'How did you do that...' by adding a sky took on colour infrared film with a conventional landscape.
Apocalypse anyone?
Folkestone
All text and images © Keith Rowley 2022
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