New ways of painting
I used to do all my art the traditional way. I used tracing paper to develop a drawing, ending up using many sheets. I'd erase too, but sometimes the drawing would become too complex to erase so I'd use little bits of tracing paper. A lightbox also came in handy but it was a bit unwieldy as the size of the lightbox was usually smaller than the drawing. So I'd end up with lots of little bits of paper and tape, then a final drawing, which I'd transfer onto watercolor paper. I would use tracing paper to trace the drawing then rub the back of the tracing paper to transfer the drawing. I tried transfer paper but found it would leave marks I could not erase.
Transitioning to a graphics tablet
Then I got a Wacom Bamboo, and found I was not very coordinated and could not do original drawings on it, so I'd scan in my drawings then color in Photoshop, but generally I wanted to only use paint.
Then I got a tablet PC, back in 2004. I could then draw in Photoshop Elements, completely on the tablet. It had no pressure sensitivity, so the line did not have light and dark parts like a hand-drawn work would. This was ok for some art, but generally I would print out my computer drawing then end up using the tracing paper transfer method anyway, but I'd use less overall paper. Then I'd paint the watercolor paper. I tried printing right onto the paper, this worked sometimes, but my printer would jam or or I'd want to make more changes and could not erase. Sometimes I'd color directly in Photoshop.
I had deadlines that were rushed so then I'd work completely on the computer, or scan in drawings and color in Photoshop.
Later I got a Wacom Cintiq, and this eliminated the whole scanning part. I practiced digital painting until my digital art was hard to distinguish from my watercolor.
What if the client wants traditional media?
But some clients wanted watercolor. The Cintiq has pressure sensitivity, so I'd draw my sketch on the computer, even being able to get the sensitive line work I wanted. Then I'd print, transfer using the tracing paper method, paint, THEN scan, and tweak any colors or even line that I wanted, then email the files to the client. I had to scan in two parts because my art was bigger than my scanner. But that was OK.
Almost all digitalSo now I use a combination of computer, watercolor, and tracing paper (and Scotch tape! Double-sided makes it easier). Some of my art is half-digital, and now that look is on purpose rather than a "tweak." So it's like a cyborg!
Camera vs. scanner
I find using a digital camera such as one on an Iphone can make better reproductions of my watercolors than can my scanner (someday I'll get a better scanner). So I take high-res photos instead of scans, tweak them digitally, and send them to the client. If I am doing an original piece of art for a show, I work it all out on my Cintiq or tablet PC with Wacom digitizer first. Click here for lots of info about using tablets to make art.