the eaisest answer to your question is "yes".
in early versions of the strip, all the colors were done with acrylic ink. then i switched to marers, but sometimes i like to do things in ink washes because the markers smell bad, or i'm just in a mood to paint. i also color in photoshop when i get a chance to use the drawing tablet at my uni's library.
i have a basic idea of what the plotline is going to be, and i'll write little scripts in my head, but mostly the dialouge happens when i'm drawing the strip for the first time. i don't have a writer, so i'm kinda free to do whatever i want. (this is both good and bad).