Instant art: Just add photons.
Hey! now I'm a "Painter of Light", too...well except for the giant printing presses, the army of assembly line painters, the lucrative tchotchke deals and the zombie-like collectors with thousands of virtually identical paintings, but it's a start...
This fake watercolor technique likely exists already out there (I don't spend much time on the various photoshop boards, web sites, mailing lists, etc.)
But I know I found it by myself, so here goes...
I found this mostly by accident, noodling about with Photoshop filters with a picture of Mom's dog that I'd scanned. Printed on some rough paper with an inkjet, it doesn't look half-bad, vastly superior to Photshop's watercolor filter.
Since that was a huge 1200 dpi scan, I'll work with something a little smaller....
Open the file in photoshop, and duplicate the background layer. Call it Palette/spatter.
On the duplicate layer, apply the Palette Knife Artistic filter. Play with the settings, because they'll vary with the effect you're looking for, and the individual image, but the object of this part is to get the broader washes of color you would expect from a watercolor painting. The settings I used were:
Stroke Size = 17
Stroke Detail =3
Softness = 6
Now apply the Spatter Brush Strokes filter. The object here is to simulate the irregular bleed into the paper that watercolor paints produce.
Keep the Spray radius down, and the smoothness up. I used
Spray Radius = 5
Smoothness = 8
Here's what it looks like so far
|After first filters|
Now duplicate this layer, call it Speckle.
On the speckle layer apply the filer Grain, from the Texture section. The object here is to emulate the concentration effect where, as watercolors dry, they tend to concentrate at the edge of area they've spread to, giving a small rim of deeper color to the painting. (This isn't true, of course of all watercolor technique, as the effect can be minimized or otherwise manipulated, but hey, this is my cheap forgery, ok?
Again keep the effect at the lower end of the settings. In this case I've used
Contrast = 15
Grain Type = Speckle
Now adjust the opacity of the Speckle layer, because it really tends to dominate otherwise
You can bring up some detail back into the image by lowering the palette/spater layer, too. I used about 50% for the speckle layer and 80% for the palette layer to produce the final, below.
| I've also got a full size (1152 x 864) version of the image.
For the terminally lazy amongst you here is a photoshop action file that does this all (more or less; the defaults are slightly different)
for more examples see here.