Although, on the whole, I prefer Adobe Photoshop to the GIMP(should, given the cost-differential), there are a few functions in GIMP that seem to be missing in Photoshop. This is the first in a series of short essays on methods I have found to work around some of these seeming deficiencies in PS. Although they are a bit more complicated than their GIMP equivalents, it shouldn't be too much trouble to store them as actions. Let's start the show...
1) Start by creating a new document. In order to save myself a bit of sanity, I'm going to create mine in greyscale with a black background.
2)On top of your background, create a new layer with a dissolve blend mode and an opacity of 100%(Actually you can vary the opacity if you wish). Fill this layer with white. Now, ain't that purty(?)... No, not so much, yet.
3)Now, create a layer mask on that top layer. Make sure you have the mask selected, and invert it to black.
4)Paint, in white, on your layer mask. That's the spermlike image below. I accidentally used a slightly soft brush, so it's already a little ragged.
5)Now, use Gaussian Blur on your sperm mask. Blur it to the desired spread width. I used a fairly large 27.5-pixel blur for this one. I have an image of the blurred mask below as well as the final spread image that results from using that mask as a dissolve.
6a)Once you have this method down, you can record it as an Action. I'll name mine, "Spread." I'll use that term in future tutorials to refer to this method for simplicity.
optional step)For additional interest, you can copy the mask into the image part of the dissolve layer. This can be useful for some methods I might describe later. If you like, you can save this as a, "Blurred Spread," action. Again, I'll be using, "Blurred Spread," as a shorthand in future tutorials. Assuming I don't forget.
note)I still haven't saved these as Actions. Me mal...