Indirect painting is when the painter paints the picture first in black and white (a grisaille) or in warm tones such as Burnt Umber. Then, after it dries, the painter applies glazes of colors over it.
However, what I wish to point out is that for glazing to be effective over a black and while underpainting, the high-key colors (bright reds, greens, and yellows) must be painted in extra-light values. Notice the values in the bottom painting above, the apples are extra light. That way, when the bright, high-key colors are applied over the apples, you will be able to maintain their intense color saturation.
Conversely, if the apples in the black and white painting were painted in darker values, the glazing over the top of them would only produce a murky color and lack brilliance.
(I don't know who painted the picture above, so unfortunately I cannot attribute it.)