In this tutorial we'll see how simple it is to enhance sky. We'll be looking at two images: One with a person in the middle and the other of a landscape.
First we'll start with the simple landscape.
You need to open your image and in the Layer Panel create a new layer. (Layer>New Layer).
Next, go to the tool bar and select the Gradient tool. On the top toolbar, make sure you have the tool which goes from the foreground to transparent (the second one on the top row) and you want to also select Linear Gradient (the first box out of the five). Also, make sure black and white colours are selected and that black is on top to darken the sky. Once you have this tool selected go to your image and from the top of the sky to slightly into the foreground (in this case the trees) holding the mouse button down draw a line and then release the mouse button.
After doing this you'll notice you have a pattern going from dark to light over your image – don't panic it should look like this!
From here go to your Layer Panel and click on the tab which says normal. After clicking on the tab a menu should pop up and in the list find the option called overlay. After doing this you'll see your sky has changed colour. If you like you can change the opacity of the image until happy but apart from that, the image is complete.
However, if you have something a little more complicated like a portrait of a person there's a few extra things you need to do.
After overlaying the portrait layer with the gradient you'll notice the portrait looks a little strong and in this case orange! This is because the gradient was applied to all the image but we're going to change that.
What you need to do is click on the gradient layer and add a layer mask. To do this, look at the bottom of the Layer Panel and find a rectangle that has a circle inside it and click it. After you've done this, hide this layer. Go to your original layer then the Select menu and Colour Range. This will open up a new window. In this window you'll see your image, a series of sliders and some pipette tools. You need to select the plus pipette tool and begin selecting the colour you want to keep which in this example is anything but the sky. The selections you make are visible in the preview screen of the Colour Range box. Anything in the preview that is white will be selected everything else will not. To refine your selection you can turn the fuzziness slider up or down. If you find you've selected too much you can also change the pipette tool to the one with a – symbol and remove some of the selections made. This process can take a while but once you're happy with your selection click OK.
It may take a few minutes for your selections to be processed but once this is complete you'll see your image is now selected with a line of 'running ants'. From here, make your gradient layer visible and click in the layer mask you created (the smaller white square in the gradient layer). In here click Alt and Backspace (delete) and you'll see what you selected is now in the layer mask. If you deselect the image you'll see the original portrait is now visible on the newly improved sky.