Just updated with some final tweaks and tips...here you go!
This is not a short/simple tutorial, so be prepared and pay attention to she screenshots. It uses the
oblique and
Drop Shadow plugins, so you'll need those in order to complete this tutorial.
With that said, here we go.
We're going to be creating a signature something like this:
Many people have asked BarkBark00 how he made his signature, and he asked me if I was going to finish the tutorial I started working on a few months back.
Start with a new image, dimensions 50 x 100 px (W x H).
Select all ( [CTRL]+[A] ) on the background layer and delete everything or start with a transparent background.
On the background layer, use the rectangle select tool to select the left half of the canvas, and bucket fill it with white.
Next, add a new layer above this one, change your primary color to white, and your secondary color to dark grey (not full black), and fill with a linear reflected gradient. Adjust the control points until it looks something like this:
With the selection still active, and while still on the top layer, apply a Gaussian blur at 3-6px.
Next, merge the top layer down into the background layer.
Apply curves to the new merged layer using settings something like this:
You should now have a silvery end-cap.
UPDATE:
In order to get the endcaps to the right proportions, we'll need to slim them down a bit.
First, we'll remove the empty space. Use the magic wand in the transparent part of the image to select it:
Invert the selection [CTRL]+[I]:
Crop the image to the selection [CTRL]+[SHIFT]+[X]:
You should have just the endcap remaining.
Assuming you started with the
left endcap, you'll want to change the canvas size (***DO NOT RESIZE*** canvas size is a different option) like so (make sure you uncheck "maintain aspect ratio"):
...which should leave you with a slimmer, trimmer endcap (that pretty much matches what's in BarkBark's sig):
For the rest of the tutorial, pretend that the endcaps are slimmer

I may go through the trouble of taking some new screenshots, but I'm not promising anything.
Now, change the canvas size again (make sure you pay attention to the settings in the dialog box). Make the width about 450px.
Delete any background color that may have showed up after you resized the canvas. Duplicate the layer you now have, and use layer -> Flip horizontal to create the other end-cap.
Create a new layer and move it to the bottom of the layer stack.
Select a rectangular area and fill it with black.
Create another new layer above the black layer, and make a shorter rectangular selection. Fill it with white.
Create a layer above the white layer and select a font (fonts that are more "blocky" work better) and type whatever text you want to appear.
Duplicate the text layer and apply a drop shadow to the text on the bottom layer. Uncheck the "Leave original image" checkbox.
Go to the text layer, and select Adjustments -> Invert Colors to make the text white.
Add a new layer below the drop-shadow, select a rectangular region from the bottom of the white rectangle to just below the text, change your primary color to light grey and your secondary color to white, and fill the selection with a linear gradient from left (light grey) to right (white).
On the text drop-shadow layer, keep the selection from the last step and use the oblique plugin to angle the shadow to the left at the bottom.
This effect will make the bottom part of the shadow not line up properly, so use the "move pixels" tool to move this part of the shadow back to the right.
Create a new layer above the text, and select a rectangular area that covers the white background area. Fill this area with the color of your choice, and change the layer blend mode to multiply and the opacity to around 200.
Create a new layer above the color layer and fill it with a pattern. If you use a pattern fill with the paint bucket tool, make sure the secondary color is set to fully transparent. The primary color should be either white or black. Change the layer opacity to around 80.
Create a new layer above the pattern layer and change your primary color to black and secondary color to fully transparent. Fill the selection with a linear gradient from left (black) to right (transparent).
Create a new layer above the black gradient and move the bottom of the selection up to just above the top of the text. Change the primary color to white (secondary color stays transparent), and fill with a linear gradient from above the top to below the bottom of the selection.
Duplicate the right-hand end-cap layer and move the new layer below the white highlight layer. Apply the drop-shadow effect.
UPDATE: We have a drop shadow to clean up and another one to add, and we'll be done.
Here:
...is a small problem. The drop-shadow from the endcap shouldn't really be visible on the background (it definitely makes the whole thing look less polished).
Make the layer with the drop-shadow for the endcap active and use the rectangle selection tool to select a rectangle that goes from the top edge of the black background rectangle to the bottom edge. It should go past the inner edge of the right endcap and past the end of the drop shadow itself. It might help to magnify the image in order to get the selection just right:
Invert the selection [CTRL]+[I]:
Press delete, and the extra shadow should be gone:
Now we just need to add one final touch, which is a small drop-shadow around the whole image. Flatten the image [CTRL]+[SHIF]+[F], select a fully transparent secondary color, and use the Canvas Size tool to increase the size of the canvas and leave a 5px transparent border all around (your settings may be slightly different, just try to have an even border):
That should leave you with something like this:
Now, we'll add a drop-shadow. X and Y offset should be set at 0, and blur radius should be set at 2:
That's it. You have now know how to make a signature like BarkBark00's.
