1. Open up your signature with no color added yet.
(Image > Adjustments > Desaturate, IF it isn't.)
2. Go to Layer > New adjustment layer > Color Balance to create a new color
balance layer above all other layers. Apply the below settings.
3. When that's done, you should have something looking like this. Remember you do not
have to use my settings, use to your liking
4. Okay now here is the main part, this might be a little tricky. Make a new layer just
below the color balance layer and start brushing with NON-render brushes(something
grunge looking/abstract/both, just make sure they are not made from renders)
in the parts that you want the other color to appear, brush in black and white only.
Make sure that some of the white brushes intercept with the black brushes, or else
you won't get the color effect later on. Make sure all of this is done on one layer and
that some of the white brushes are on the black brushed part, or vice versa(on the same
layer).Should look like this.
5. Now go to Layer > layer style > Blending options and go to
color overlay. Set the mode to Color Burn or linear burn, but make sure
to choose a very light color.
6. If you did everything right in the last 2 steps, it should look something like this.
7. You should add a level layer to give it some extra dept. Layer > New adjustment
layer > Levels. I added these settings to mine. Use a different setting to suit
your sig.
8. Here's how mine look now.
9. Add some extra effects, some text, a render and you done.