Creating a Portal Effect

This tutorial is not intended only for creating a portal effect, but also to teach you how to use multiple filter effect one after another. Create a new document, 1000x1000 pixels, white background.

Go to Filter > Render > Clouds

Then use Filter > Pixelate > Mezzotint with "Long Strokes" option activated. Your image should look like this:

Now go to Filter > Blur > Radial blur and use these settings: Amount:100, Method: zoom, Quality: best. Your image should look like this:

Now use Filter > Distort > Twirl and set it to 200.

Now duplicate the layer and on the newly created layer go again to Filter > Distort > Twirl but this time apply it with a -400 value. Change the blending mode of this layer to "Lighten". Your image should look like this:

Merge the two layers now. Go again now to Filter > Distort > Twirl and set it to 200. Now press CTRL+U or Go to Image > Adjustments > Hue/Saturation and use any settings you like. I used Colorized, Hue: 200, Saturation: 30, Lightness: 0