In Photoshop there are many ways to color the images.

You can use gradients, just plain color fills or brushes.

I will use gradient to fill my image with color.

So create a new layer and fill in with this gradient. Note that the layer mode is set to Darken.







Moreover I've added some layer styles to my gradient layer.







Here is our result.

Select the layer on what you've painted the base silhouette and add a Threshold adjustment layer.











Switch the layer mode to screen and set the opacity to 9%.



Now, I want to add some foreground elements. I will use the brush we've used before In the very beginning of the tutorial.