How to replace skies in Photoshop is something we are asked about frequently. When replacing them with skies from bracketed exposures our job is a little easier. But, when we’re replacing them with entirley new skies we are faced with a great challenge. This challenge is magnified when the sky line is filled with fine details, such as trees.
Dennis Mitchell challenge me to replace the sky in a landscape. This challenge was particularly challenging and an issue that would be faced regularly when shooting scenes with trees against the sky. Where highlights hit the trees, this can cause many issues in replacing a sky. I show a unique technique for dealing with this type of replacement. If the sky we were dropping in was from a set of bracketed exposures of the exact same scene our job would be easier.
In this example the exposure for the waterfall and the trees has been exposed well for the shadows. When we expose for the shadows we tend to over expose the highlights in the image. In this case by exposing for the shadows, we have lost a lot of the finer detail in the tree branches and leaves.
The first thing I do is mask in the sky. This involves creating luminosity masks selections of the sky and applying it to the sky image. I then run through a series of steps to clean up the foreground that was affected, and position the sky.
This is where we tackle the difficult issue of light branches and leaves on the trees. Because they are so light in the image, there is nothing that we can do to blend them naturally, if we leave them as they are. So, I make a lights luminosity masks selection and use that on a curves layer to significantly darken the highlights. By doing this I’m able to make the edges of all the leaves and trees look natural against the sky.
By significantly darkening the highlights, I am also affecting areas of the image that I don’t want affected. Using a technique that I call masking the mask, I drop the curves adjustment layer into a group. With a black mask on that group, I hide the effect of the darkening. Then using a white paint brush on the group layer, I can bring the effect back to where I want it.
Often when you replace the sky in an image, with the sky from a completely different scene is it doesn’t look natural. Often we’re replacing a dull white or blue sky, with a colourful and vibrant sky. The problem with this is that typically vibrant or moody skies are reflected into the landscape. As a result, we need to spend some time modifying the foreground of the image to better match the sky that we have used in the replacement.
I run through a series of steps to bring the moodiness of the image down. I also cover some steps to modify the colour in the image to reflect the colour in the sky.