34. Using the Polygonal Lasso tool, create a shape that gives the appearance of light exploding from the doorway.

35. With this selection active, create a new Curves Layer and rename it “Light”

36. Adjust this layer to be a bit brighter by pulling up the center of the line.

37. Now hold Command and click on the layer mask attached to your “Light” Curves Layer. This will give you a selection that matches your mask.

38. Now go: Select>Inverse to get the opposite area selected and create another Curves Layer with the active selection. Name it “Dark”

39. You now have control over the darkness of the environment as well as the brightness of the artificial light from the door. Next, you need to Feather these Curves Layers to make them more realistic. Clicking directly on the masks (not the layers themselves) will allow you to directly influence the mask’s Density and Feather. I recommend adjusting only the Feather. Bring it up to between 100px-200px on both “Light” and “Dark”.