Now the fun part! — And the heart of this tutorial. I’ve chosen to use a background that could really shine some colors on to the subjects using highly lit streets and neon signs. Here we can place a pink light on the left side, a blue on the right and an ambient white from behind. You can add even more but for our purposes here, I’ll demonstrate with these 3 imaginary light sources.

Before we go in, save a new file and merge all of the color layers into one since we’ll be adding even more color layers sandwiched in between the background and the line art. Add 3 new layers above the colors for the 3 separate light paints. The Layers panel should look like something below: A background layer with a flattened color layer, a blue, pink and white layer topped with the line art.

Select your pink and the white for your foreground and background colors. Draw your selections with the Lasso Tool holding Shift with each cut and paint with a large paintbrush set at about 25% opacity and 50% flow. This will allow you to build up the color. With every stroke get closer to the edge as the light will be more intense the closer the edge of the surface is to the light source. The bracket keys “[ ]” are hotkeys that increase and decrease the size of your brush. Go smaller as you stroke closer to the edge. Toggle to white and click your white color layer and gently add highlights to the edges. Having your white and pink to easily toggle and going back and forth between layers will make the process more intuitive.

Here is another example done with a selection on the glove.

Now focus on the other neon blue light source. Since we imagine it on the right side of the frame the intensity of this color will shine on the rightmost edges of our subjects. Here is an example of the above technique when applied to the right side of Sarah with the blue in conjunction with the pink.

Continue the process on all three layers in cutting the selections. Notice the stark difference after revealing the reflected light layers