Several years ago I visited numerous tutorials on creating lightning in Photoshop. I recently revisited them to see if things had changed, but for the most part lightning tutorials render the effect from clouds, and go though numerous steps to get to the finished product. Unfortunately, when you are done you have created something that looks similar to lightning, but it’s totally random. If it doesn’t fit your needs, you have no choice but to try again.
With my method, lightning is drawn with the smudge tool, thus you direct the size, direction, and number of bolts. All of the small branches are pulled from the main bolt with the same smudge tool. While this method requires some artistic talent, the end result is a good replication of lightning bolts that you actually see, and can be indistinguishable from the real thing.
First open a new canvas, approximately 600 pixels wide x 1200 pixels high and fill with a dark color of your choice. Create a new layer called lightning and choose white, and with your brush tool create a single dot at the top of your canvas, approximately 60 pixels at 0% hardness. If you don’t want this glow in your image, it can be erased at any time after you have created your lightning.
With your layer highlighted, choose blending options and select outer glow and inner glow. On outer glow, choose a light blue, set the opacity at about 30%, noise at 0%, spread at 15-20%, size 15-20 pixels, range at 50%, and jitter a 0%. On inner glow choose a dark blue, or red if you prefer, opacity at 75%, noise 0%, choke 0%, size 2 pixels, range 50%, and jitter 0%. Note that none of these numbers are fixed, just a good starting point.
Now the fun begins. With the smudge tool set at 100 % strength with a 4-6 pixel brush, depending on the size of the trunk line you want, place the brush in the center of the white dot and hold down you mouse button and drag, using abrupt or jiggly movements as you head to the bottom of your canvas. To create branches you can either use the same brush by carefully just touching the edge of the bolt, then dragging from there and the branch will automatically be smaller. If you have difficulty, choose a smaller brush, say 2-3 pixels. When done, always save as a PSD and never flatten the image. Another option is to turn off the background color so it is transparent and save as a PNG.
Now that you have one bolt of lightning you may duplicate it, stretch it, distort it, rotate it, or anything else you want now that it’s in its own layer. Add it to a picture by simply using the move tool and dragging it into the image.