Parametric city lights at night problem

[Roei Tzoref]

I would approach it this way:

1. clean the already lighted map. make it dark. I have managed to do something pretty fast with a dark blur solid set to darker color mode

you can work on it in photoshop to put some of the texture back.

2. separate the lights from the background. it’s easy because they are bright over very dark. you can set the layer to luma matte it’s duplicate with levels to make it more contrasty.

3. use any effect or combination of effects or setup that uses a luminance as a base for reveal. you could use fractal noise. I use CC Image wipe set to Hue. this gives me a cool base for the first lights. of course you could mask the parts you want.

4. use another layer for the main lights. same gradient map set to luminance. this will be the big lights. together with the previous layer it looks like this:

if you set masks you can control more of the dispersion. but the hard part of getting those little light in my opinion gets done by the using the luminance information this way or similar way. there are ways to perfect this right now the lights seem a bit pixelated or not detailed enough but I believe this could be perfected this way and with a reasonable amount of time 🙂 hope to see other ideas here.