Introduction
Today, still the most famous science-fiction weapon of choice is the infamous lightsaber. The swords of light that Jedi's and Sith use to battle in the movies of Star Wars.
Ever since the birth of graphic-design programs, people have been editting lightsabers in their own photo's and videos to look more like their favorite heroes. Yeah I tried it as well.
With this tutorial you can as well. It may take a Jedi to fabricate a real lightsaber, but it takes a novice to build one in Photoshop!

The Hilt
There are 2 ways to do this tutorial: start from scratch or add a lightsaber to an existing photo. If you're choosing the last method, skip these next 2 steps.
If you're starting from the beginning, you're going to need a saber-hilt. You can use yours from HD-StarWars images or just from MasterReplicas. Make sure you use a desired tool like the Pen-Tool to extract the image from its background, if needed.

Use CTRL+T to rotate and scale the lightsaber so that it's gonna fit the screen when we're done.

The Beam of Light
To create the glowing sword, grab the Rounded Rectangle-Tool and set the feather-radius to something really high. We're going to make a thin sword, with round corners. If the feather-radius of the Rounded Rectangle is higher than the actual corners, it will turn the corners into a complete round shape, the same as a lightsaber or a tube.
So depending on the size of your sword (in Photoshop), use a radius that is larger than your actual corners. I set mine for 100.
Then just simply click and drag and make a perfect long shape. Fill this shape with White on a new layer.
Drag the layer to the hilt and use an Eraser or the Pen-Tool to remove the whiteness overlapping the hilt.

The Glow
Now press CTRL+J 2 times to duplicate the layer 2 times. Hide the original, because you might need it later. Now, for the first duplicate, go to Filter>Blur>Gaussian Blur and set it to 2-4.. make sure it's very mild.
For the second layer, make it a little larger. Like 5-20. Not too large though!

Now add the following layer-style to the first duplicate:

And the same settings, with a higher size-amount for the second duplicate:

And you will notice that your lightsaber looks perfect.
Note that I chose for the color blue. To change this into Green, Purple, Red or Yellow, simply just edit both blue glows on both blurred layers. You can also variate making one Red and the other Blue giving you a unique Purple!

Or maybe you want to play around and add lightsabers to existing movies or photo's. Check down below what I did with the famous fighting-scene from the movie 300.
I changed all the swords to lightsabers using the method we just did. It's just a matter of rotating and placement and you're done. Also try to play with a soft brush on a new layer in the color of the lightsaber. Brush around the area's where the saber-light casts on the body and gently brush on those area's.
When you're done, lower the opacity and set the blending-mode to OVERLAY.

Conclusion
As you can see below, you can deviate with the colors all you want. I kept the hilt the same for this tutorial, but if you can find better hilts or more hilts, don't even hesitate and try it out!
Just keep in mind that if you wish to make the sabers the same color as the movies, you take a good look at the image below or at the movie itself.
I'm really interested in the cool outcomes where you placed a lightsaber in your hand! Post the URL in the comments if you got a nice one!

May the Force be with you!