I created this portrait entirely in SketchBook, using only a few brushes, but trying for interesting backlighting and smooth skin tones. I took a lot of time to get the drawing right, before I started painting. I think this made a huge difference in the realism of the portrait.
I opened a blank canvas in SketchBook and I created this sketch using a pen brush. When I made drawing errors, I sometimes erased and redrew. And sometimes I used the freehand lasso under the Select tool to select an area, such as her mouth, and then used the Move tool and Transform tool to resize and reposition it.
On a new layer under the sketch layer, I used the tattoo inker brush to paint a blue background in various shades of blue. I used lighter shades of blue to indicate the sources of light, and I used darker shades to indicate shadow. I let some white space show between some of the brush strokes. Then I filled the bottom layer with a dark blue, which then shows between some of the brush strokes.
On a new layer above the blue layers and underneath the sketch layer, I painted the hair and eyebrows with the tattoo inker brush, using various shades of brown. I used the lighter shades to indicate areas where the hair was lit by direct light from the left side of the canvas and where it was backlit, giving her a kind of glowing halo.
On the bottom-most layer, I decided to use a darker shade of blue for more contrast as it shows through areas of the lighter blue background that I painted. I used the Fill tool to fill the layer with dark blue.
On another new layer above the background layers and under the hair layer, I used the tattoo inker brush to paint her shirt and a gold pendant. Again, I let the background show through in places between the strokes.
On several new layers above the shirt layer and below the hair layer, I used the tattoo inker to paint the shades of her skin. I imagined her face touched by direct light from the left side of the canvas, giving her face some rim light, and lit by reflected light from below.
On several new layers above the skin layers, I used the tattoo inker brush to paint her eyes. I used different layers for the iris, pupil, whites of the eyes, shadows in the corners of the eyes, and two shades of lighter blue for depth in the irises, and catchlights.
I didn’t want the dark blue background showing through in between the brush strokes on her skin. So on a new layer just above the background layers, I used the tattoo inker brush to paint white underneath her head and neck. On a new layer just above the shirt layer, I used the tattoo inker brush to paint highlights where light hits the shirt. I used HSL adjustments on the brownish skin layer to lighten the skin a bit. And I used one of the colorless brushes to smooth out the skin tones. On another new layer above the hair layer, I used the tattoo inker brush to paint more detail onto her hair, taking care to show the backlit areas and shadow areas appropriately.
On the appropriate layers, I painted more color onto her lower lip, and more highlights below her lower lip.
I again lightened some of the layers with her skin tones, I smoothed a bit more of the skin tones with a colorless brush, and I used the cashmere eraser to erase some edge errors on various layers. On the sketch layer, I used the eraser to erase many of the sketch lines.