Step 5

Now we'll convert this layer to an outline. To do this, go to Filter> Stylize> Find Edges

Step 6

Here's what the image looks like after using the Find Edges filter.

Step 7

Now we have the outline, but the problem with it is that the outlines are black and not white like it's supopsed to be in a blueprint. To fix this, simply invert the layer by pressing Ctrl+I or going to Image> Adjustments> Invert. This will create an inveretd layer and now the outlines are white. To make this layer blend with the layer below, set the blending mode to Screen. The Screen blending mode makes only the bright areas of the layer visible. So the white outlines will show but the black background will disappear to reveal the layer beneath it.

Step 8

Now we're going to add a new layer with the blue color. For this, we'll use a Solid Color layer. Why not just create a new layer and fill it with blue? You can do that, but it's not a good way of doing it. Using an adjustment layer will keep the filesize small and is good practice to use adjustment layers whenever possible. In the Layers pallet, click on the "New Adjustment Layer" button and a menu should appear where you can select Solid Color from the top of the list.