I use Color It! 4.1 (now Digimage Color It! 4.5) on an Apple iMac G3 using an old Wacom tablet and stylus. This is a graphics package akin to Photoshop. I find Color It! simpler than Photoshop or others like Painter, etc. Color It! provides endless panels into which one can create using airbrush, pencil, erasers, smudgers, etc in differing sizes and draw patterns. One big virtue is that one can go back quickly 16 steps or so . For the artist drawing directly onto the screen it has a directness close to painting with small and large soft pastels. I tend to use millions of colours on a 10mgb setting at A4 size, which is good for sending as a jpeg file. I do NOT import any other images via cut and paste to the Macintosh from any other source other than those I might have created previously myself, drawing directly onto the screen from blank.
After a deal of practice the ability to sketch on screen becomes as easy as with any other medium. Time and practice is required to develop the mind to accept drawing and painting without the tactile quality and sound provided by conventional means. I have glued fine cotton canvas to my old wacom tablet to give the wacom stylus some texture and holding quality and sound.
I first sketch in light grey tones until the composition is fixed. Next, by erasing and fudging, I pull the whole together with tighter drawing, then fill in the tones until I have a monochrome grey or sepia underdrawing. When painting flesh this is followed by warm and cool tones of Venetian reds and cobalt blues in the shadows. A slight blurring of the whole or portions can be helpful in the early stages. I am then ready to put in colour washes all the while tightening up the drawing. The high lights and very dark shadows are now applied and the work is ready for the full coloured and drawn detail. This is the time consuming part. I tend to use the 'Airbrush' tool in the early stages, and the 'Brush' tool for finishing details. I use all the powerful devices the computer provides for enlarging and reducing, lightening and darkening and blurring and occasionally I overlay the black and white image on top of the same saved coloured image to get a more sombre look as in old prints.
The most powerful advantage of the medium is that you can enlarge the image down to such detail that you can manipulate each pixel if required. Colours can be overlaid as in glazing, or laid down opaquely. Portions of the picture can be adjusted by enlarging, reducing, flipping, distorting, or moving without any repainting.
If you are linked to a sophisticated printer such as a Giclee, or one which has multiple toners and can take fine art papers, then you can draw, save, and print as many high quality copies as you desire at any stage, in an instant. Imagine what Rembrant or Toulouse-Lautrec would have done with this medium. You also have the ability to create works as large as a printer can handle by just the small movements of a stylus.
The texture of the print can be close to the 'Aquatints' of the past. By saving at each stage, if you overwork your image, then you can simply go back and pick up again from an earlier step. If you have 50 numbered stages saved for the work, then you have plenty of choice of steps to print from.
Consider the saving on artist's materials, plus a full palette of colours, including, on screen, bright royal purple which is not available in pigment form. No brushes to clean. No smells of thinners.
A simple still life, or a self portrait is good to start with. I have done some life drawing directly onto the screen, but the medium is not kind or helpful for quickly sketched works. As with painting miniatures, painting digitally has to be developed before it begins to work. One can draw landscapes outside on a laptop and then have the ability to send your Jpeg image anywhere in the world instantly without scanning. So you can sit in St Mark's Square, Venice, then send it home to your friends via the internet. Better than sending a mobile phone photo anyday!.