: Invert the Gradient Map's mask to black ( Ctrl+I ). Use a soft White Brush (B) with a low flow (around 10%) to paint the glow onto the floor, walls, or subject near the portal.

: In the Properties panel, set the Fill to None and the Stroke to White . A stroke weight of approximately 20 pixels works well for a standard portal.

: Duplicate the original ring and set its blend mode to Color Dodge with a slightly smaller stroke size to create a blindingly bright "hot" core. 4. Integrate with the Environment