Now we will add some highlights to our dark outlines in order to give them some 3d volume. Create a new layer in the Dark Buildings group and name it Highlight. Clip this layer to the outline layer we created in step 18 (for clipping refer to step 12). We assume that the light comes from the left up side of our image so the highlights will have to be on the left side of the building outlines. Select a white round soft brush at 10% Opacity and paint some highlights on the left side and top of each building. Don’t overdo, be subtle.
When light hits an object we usually notice a very sharp bright line on the corner or top of it. This is called specular highlight and it gives our objects a nice look. Create a new layer and clip it to the highlights layer. Name this layer Specular Highlight. With a white brush at 30-40% Opacity and 1px size paint some subtle specular highlights on top and left side of the buildings. Again, be subtle.
Now let’s create the second city outline. Repeat the steps 18 to 20 but increase the size of the Mosque brushes and place them a little higher than the Dark Buildings outline. Name the newly created group Medium Dark Buildings and place this group below the Dark Buildings group in the Layer Palette. Lower the opacity of the Medium Dark Buildings to 85%.
For the last city outline we will use a mosque from a picture. Open file Mosque and make a selection of the mosque using the Lasso Tool or the Pen Tool. Copy and paste into our image. Right click the pasted layer and choose Convert To Smart Object. Use Free Transform (Ctrl + T) to place the mosque behind the two other building outlines.
Now let’s fill the Mosque with black color in order to make it an outline. There are multiple ways to do that but I went for a Adjustment Layer solution. Create a new Curves Adjustment layer and place it above the Mosque layer. Clip the Curves layer to the Mosque layer and drag the right point of the curve all the way down.
Select both the Mosque and the Curves layer and group them together (Shift – click each and press Ctrl + G) and name the group Big Mosque. Add a layer mask to the group. Shift click both the Dark Mosque layer (the layer where you applied the brushes) and the Medium Dark Buildings. This will create a selection of both. Now click back on the layer mask of the group Big Mosque and press D to set default colors and Alt + Backspace to fill selection with black. This will prevent the ugly look caused by stacking multiple transparent layers on top of each other.
Apply both a specular highlight layer and a highlight layer to the Big Mosque group (as we did in step 18 to 20) and group all these layers together. Name the new group Light Buildings.
It starts to look good but we still need to make the city look more real. And the best way to make a city look real is to add smoke/dust. Create two new layers and name them Smoke. Place one between Dark Buildings group and Medium Dark Buildings Group. Place the second one between Medium Dark Building group and Light Building group. Choose a soft white brush at 1% Opacity and paint some smoke/dust (just draw some loose horizontal lines). The effect will be barely visible but it helps selling our city.