ASDP is simply one of the terms I use to describe my digital painting technique. A couple of others are photo-synthesis, graphic interpretations, and micro-painting.
I use a unique program called a paint synthesizer. Also known as Studio Artist 3.0, the program allows you to selecta source photograph and have it re-rendered to a canvas (paint window). Just like a music synthesizer has patches to make your notes sound like a wide variety of instruments, SA3 has patches that can make your original photo look like a pencil sketch, a watercolor, oil painting or any of thousands of other natural media presets that are included with the program.
SA3 lets you build and blend layers of these renderings within the program, although I prefer to save the individual renderings out as files which I then load into Photoshop. I have about a dozen or so patches that I've found work well to create the styles of painting I like to use. There is one patch that creates a soft, blurry watercolor wash that I tighten up with a very small soft brush. A rough circular brush cloner that gives me a rough brush texture that I can modify with PS filters. A very small brush cloner to provide detail. A hard edged small square point detail color sketcher which adds some variation and detail to the images. A pencil outliner and a lum hatch sketcher to provide some edges and extra detail to shadows round out the primary ones I tend to favor. I've yet to explore all the thousands of other patches available but I try to sample a few new ones every now and then.
After rendering out these layers I import them into PS and begin rebuilding the image from these layers. Mind you most of these layers only vagely resemble the original photo but as I begin with the watercolor wash as the background layer and begin to add the other layers selecting different blending styles for each layer. Darken for some layers, lighten for others, color burn often for the edge layers. One trick I often use is to import the original image as a layer and apply the Stylize-Find Edges filter on it to create nice pencil or highlight layers (by inverting and using the color dodge or screen blend option).
Every image is different and how I approach it depends on the look I wish to acheive. By playing with the layer order, blending style and level of transparency I can acheive remarkable control over the look of the final image. Highlights can have one type of brush stroke, shadows another. Layers can be used to lighten areas and combined with layer masks. Individual layers can have filters applied to them or curves to provide even more control. I often sharpen the layers individually so I can use different radii on the unsharp mask filter to accentuate certain brush strokes.
I've found the technique works most successfully on my nature abstracts and find it helps to further abstract the subject and remove the initial focus on the details. What I have found amazing is actually how much tonal detail is still preserved in spite of the micro-painting process.