To complete the picture, I added an image to the first plan. This is our main stage. Go to File > Place…/Place Embedded and open city image. First you need a flip it. Right – click in Transform Mode > Flip Horizontal… (Ctrl/Cmd+ T or Edit > Free Transform). Then resize image to size of working field and now the most interesting – you need to align the perspective of the image that the city did not go to the left, and was flat in the frontal projection. Right click > Perspective… Use the corner points to “squeeze” the image itself and the side point, to raise or lower the slope of the image. Try not to overdo it and do as shown in the image below.
Now remove the sky. To make a selection, use Color Range… Go to Select > Color Range… and set Select: “Sampled Colors”, eyedropper with “+” in this window or hold Shift and spend all the shades of the sky. Be careful not to add the color of the town. To make the selection more accurate, set Fuzziness to 20. This method is very good and at skilful use, make easier selection of objects when their background is different in color.
It remains only to add a layer mask. Hold Opt/Alt (to add inverse layer mask) and click on “Add a mask” icon or go to Layer > Layer Mask > Hide Selection.
We now present the city in accordance with the general atmosphere. I convenient to use for this useful adjustment layer “Gradient Map”. Go to Layer > New Adjustment layer > Gradient Map… or use “Add adjustment layer” icon on bottom of Layer panel. Right away make from this layer a clipping mask by using icon at the bottom of this window.
Then click on gradient to create a new gradient. At the top of the dialogue box, on the right side there is a small gear. Click on it to open additional properties. The lower list is available Photoshop default gradients. Add “Photographic Toning” and in the popup window click “Append”. Use blue gradient shown below. Set Blending Mode to “Hue” to change color but leaves brightness and saturation as on original image.
Repeat step 4 for this image to this part of the city was in the general atmosphere and did not stand out. But this time Blending Mode “Screen”, Opacity: 25, Fill: 65.
What could be the poster without fanning and tense atmosphere (in the example of this picture)? The sky is very well managed and complements the mood and story of the picture (because we plan that we want to get). Place image of sky and resize it to the size of the working field. But do not rush to apply the changes. Take the midpoint of the bottom and move up it a bit. This will change the perspective of clouds that will help harmoniously and correctly place them in the sky in accordance with the city.
Use any portion of the sky, but I liked the right part. It is intense and harmonious. The remaining parts a much overload the picture or not expanding it. Before proceeding further, I removed the noise from the photo that it does not spoil the final result. Go to Filter > Noise > Noise Reduction… In window that appear set Strength to 10, Preserve Details to : 10%, Reduce Color Noise to 10% and check box on “Remove JPEG Artifact”. This will be enough to get rid of the noise and preserve details. If you want to achieve good results you have to take care of every detail and be careful.